assignment operator for string in c

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In C programming, a string is a sequence of characters terminated with a null character \0 . For example:

When the compiler encounters a sequence of characters enclosed in the double quotation marks, it appends a null character \0 at the end by default.

• How to declare a string?

Here's how you can declare strings:

Here, we have declared a string of 5 characters.

• How to initialize strings?

You can initialize strings in a number of ways.

Let's take another example:

Here, we are trying to assign 6 characters (the last character is '\0' ) to a char array having 5 characters. This is bad and you should never do this.

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Arrays and strings are second-class citizens in C; they do not support the assignment operator once it is declared. For example,

Note: Use the strcpy() function to copy the string instead.

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Even though Dennis Ritchie was entered in the above program, only "Dennis" was stored in the name string. It's because there was a space after Dennis .

Also notice that we have used the code name instead of &name with scanf() .

This is because name is a char array, and we know that array names decay to pointers in C.

Thus, the  name  in  scanf() already points to the address of the first element in the string, which is why we don't need to use & .

How to read a line of text?

You can use the fgets() function to read a line of string. And, you can use puts() to display the string.

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Here, we have used fgets() function to read a string from the user.

fgets(name, sizeof(name), stdlin); // read string

The sizeof(name) results to 30. Hence, we can take a maximum of 30 characters as input which is the size of the  name string.

To print the string, we have used puts(name); .

Note: The gets() function can also be to take input from the user. However, it is removed from the C standard. It's because gets() allows you to input any length of characters. Hence, there might be a buffer overflow.

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Strings can be passed to a function in a similar way as arrays. Learn more about passing arrays to a function .

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Strings and pointers.

Similar like arrays, string names are "decayed" to pointers. Hence, you can use pointers to manipulate elements of the string. We recommended you to check C Arrays and Pointers before you check this example.

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Commonly used string functions.

• strlen() - calculates the length of a string
• strcpy() - copies a string to another
• strcmp() - compares two strings
• strcat() - concatenates two strings

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Next: Execution Control Expressions , Previous: Arithmetic , Up: Top   [ Contents ][ Index ]

7 Assignment Expressions

As a general concept in programming, an assignment is a construct that stores a new value into a place where values can be stored—for instance, in a variable. Such places are called lvalues (see Lvalues ) because they are locations that hold a value.

An assignment in C is an expression because it has a value; we call it an assignment expression . A simple assignment looks like

We say it assigns the value of the expression value-to-store to the location lvalue , or that it stores value-to-store there. You can think of the “l” in “lvalue” as standing for “left,” since that’s what you put on the left side of the assignment operator.

However, that’s not the only way to use an lvalue, and not all lvalues can be assigned to. To use the lvalue in the left side of an assignment, it has to be modifiable . In C, that means it was not declared with the type qualifier const (see const ).

The value of the assignment expression is that of lvalue after the new value is stored in it. This means you can use an assignment inside other expressions. Assignment operators are right-associative so that

is equivalent to

This is the only useful way for them to associate; the other way,

would be invalid since an assignment expression such as x = y is not valid as an lvalue.

Warning: Write parentheses around an assignment if you nest it inside another expression, unless that is a conditional expression, or comma-separated series, or another assignment.

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Assignment Operators in C

In C, the assignment operator stores a certain value in an already declared variable. A variable in C can be assigned the value in the form of a literal, another variable or an expression. The value to be assigned forms the right hand operand, whereas the variable to be assigned should be the operand to the left of = symbol, which is defined as a simple assignment operator in C. In addition, C has several augmented assignment operators.

The following table lists the assignment operators supported by the C language −

Simple assignment operator (=)

The = operator is the most frequently used operator in C. As per ANSI C standard, all the variables must be declared in the beginning. Variable declaration after the first processing statement is not allowed. You can declare a variable to be assigned a value later in the code, or you can initialize it at the time of declaration.

You can use a literal, another variable or an expression in the assignment statement.

Once a variable of a certain type is declared, it cannot be assigned a value of any other type. In such a case the C compiler reports a type mismatch error.

In C, the expressions that refer to a memory location are called "lvalue" expressions. A lvalue may appear as either the left-hand or right-hand side of an assignment.

On the other hand, the term rvalue refers to a data value that is stored at some address in memory. A rvalue is an expression that cannot have a value assigned to it which means an rvalue may appear on the right-hand side but not on the left-hand side of an assignment.

Variables are lvalues and so they may appear on the left-hand side of an assignment. Numeric literals are rvalues and so they may not be assigned and cannot appear on the left-hand side. Take a look at the following valid and invalid statements −

Augmented assignment operators

In addition to the = operator, C allows you to combine arithmetic and bitwise operators with the = symbol to form augmented or compound assignment operator. The augmented operators offer a convenient shortcut for combining arithmetic or bitwise operation with assignment.

For example, the expression a+=b has the same effect of performing a+b first and then assigning the result back to the variable a.

Similarly, the expression a<<=b has the same effect of performing a<<b first and then assigning the result back to the variable a.

Here is a C program that demonstrates the use of assignment operators in C:

When you compile and execute the above program, it produces the following result −

C Programming Tutorial

• Assignment Operator in C

Last updated on July 27, 2020

We have already used the assignment operator ( = ) several times before. Let's discuss it here in detail. The assignment operator ( = ) is used to assign a value to the variable. Its general format is as follows:

The operand on the left side of the assignment operator must be a variable and operand on the right-hand side must be a constant, variable or expression. Here are some examples:

The precedence of the assignment operator is lower than all the operators we have discussed so far and it associates from right to left.

We can also assign the same value to multiple variables at once.

here x , y and z are initialized to 100 .

Since the associativity of the assignment operator ( = ) is from right to left. The above expression is equivalent to the following:

Note that expressions like:

are called assignment expression. If we put a semicolon( ; ) at the end of the expression like this:

then the assignment expression becomes assignment statement.

Compound Assignment Operator #

Assignment operations that use the old value of a variable to compute its new value are called Compound Assignment.

Consider the following two statements:

Here the second statement adds 5 to the existing value of x . This value is then assigned back to x . Now, the new value of x is 105 .

To handle such operations more succinctly, C provides a special operator called Compound Assignment operator.

The general format of compound assignment operator is as follows:

where op can be any of the arithmetic operators ( + , - , * , / , % ). The above statement is functionally equivalent to the following:

Note : In addition to arithmetic operators, op can also be >> (right shift), << (left shift), | (Bitwise OR), & (Bitwise AND), ^ (Bitwise XOR). We haven't discussed these operators yet.

After evaluating the expression, the op operator is then applied to the result of the expression and the current value of the variable (on the RHS). The result of this operation is then assigned back to the variable (on the LHS). Let's take some examples: The statement:

is equivalent to x = x + 5; or x = x + (5); .

Similarly, the statement:

is equivalent to x = x * 2; or x = x * (2); .

Since, expression on the right side of op operator is evaluated first, the statement:

is equivalent to x = x * (y + 1) .

The precedence of compound assignment operators are same and they associate from right to left (see the precedence table ).

The following table lists some Compound assignment operators:

The following program demonstrates Compound assignment operators in action:

Expected Output:

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Assignment operators.

Assignment operators modify the value of the object.

[ edit ] Definitions

Copy assignment replaces the contents of the object a with a copy of the contents of b ( b is not modified). For class types, this is performed in a special member function, described in copy assignment operator .

For non-class types, copy and move assignment are indistinguishable and are referred to as direct assignment .

Compound assignment replace the contents of the object a with the result of a binary operation between the previous value of a and the value of b .

[ edit ] Assignment operator syntax

The assignment expressions have the form

• ↑ target-expr must have higher precedence than an assignment expression.
• ↑ new-value cannot be a comma expression, because its precedence is lower.

[ edit ] Built-in simple assignment operator

For the built-in simple assignment, the object referred to by target-expr is modified by replacing its value with the result of new-value . target-expr must be a modifiable lvalue.

The result of a built-in simple assignment is an lvalue of the type of target-expr , referring to target-expr . If target-expr is a bit-field , the result is also a bit-field.

[ edit ] Assignment from an expression

If new-value is an expression, it is implicitly converted to the cv-unqualified type of target-expr . When target-expr is a bit-field that cannot represent the value of the expression, the resulting value of the bit-field is implementation-defined.

If target-expr and new-value identify overlapping objects, the behavior is undefined (unless the overlap is exact and the type is the same).

In overload resolution against user-defined operators , for every type T , the following function signatures participate in overload resolution:

For every enumeration or pointer to member type T , optionally volatile-qualified, the following function signature participates in overload resolution:

For every pair A1 and A2 , where A1 is an arithmetic type (optionally volatile-qualified) and A2 is a promoted arithmetic type, the following function signature participates in overload resolution:

[ edit ] Built-in compound assignment operator

The behavior of every built-in compound-assignment expression target-expr   op   =   new-value is exactly the same as the behavior of the expression target-expr   =   target-expr   op   new-value , except that target-expr is evaluated only once.

The requirements on target-expr and new-value of built-in simple assignment operators also apply. Furthermore:

• For + = and - = , the type of target-expr must be an arithmetic type or a pointer to a (possibly cv-qualified) completely-defined object type .
• For all other compound assignment operators, the type of target-expr must be an arithmetic type.

In overload resolution against user-defined operators , for every pair A1 and A2 , where A1 is an arithmetic type (optionally volatile-qualified) and A2 is a promoted arithmetic type, the following function signatures participate in overload resolution:

For every pair I1 and I2 , where I1 is an integral type (optionally volatile-qualified) and I2 is a promoted integral type, the following function signatures participate in overload resolution:

For every optionally cv-qualified object type T , the following function signatures participate in overload resolution:

[ edit ] Example

Possible output:

[ edit ] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[ edit ] See also

Operator precedence

Operator overloading

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Assignment operator in c.

Last Updated on June 23, 2023 by Prepbytes

This type of operator is employed for transforming and assigning values to variables within an operation. In an assignment operation, the right side represents a value, while the left side corresponds to a variable. It is essential that the value on the right side has the same data type as the variable on the left side. If this requirement is not fulfilled, the compiler will issue an error.

What is Assignment Operator in C language?

In C, the assignment operator serves the purpose of assigning a value to a variable. It is denoted by the equals sign (=) and plays a vital role in storing data within variables for further utilization in code. When using the assignment operator, the value present on the right-hand side is assigned to the variable on the left-hand side. This fundamental operation allows developers to store and manipulate data effectively throughout their programs.

Example of Assignment Operator in C

For example, consider the following line of code:

Types of Assignment Operators in C

Here is a list of the assignment operators that you can find in the C language:

Simple assignment operator (=): This is the basic assignment operator, which assigns the value on the right-hand side to the variable on the left-hand side.

Addition assignment operator (+=): This operator adds the value on the right-hand side to the variable on the left-hand side and assigns the result back to the variable.

x += 3; // Equivalent to x = x + 3; (adds 3 to the current value of "x" and assigns the result back to "x")

Subtraction assignment operator (-=): This operator subtracts the value on the right-hand side from the variable on the left-hand side and assigns the result back to the variable.

x -= 4; // Equivalent to x = x – 4; (subtracts 4 from the current value of "x" and assigns the result back to "x")

* Multiplication assignment operator ( =):** This operator multiplies the value on the right-hand side with the variable on the left-hand side and assigns the result back to the variable.

x = 2; // Equivalent to x = x 2; (multiplies the current value of "x" by 2 and assigns the result back to "x")

Division assignment operator (/=): This operator divides the variable on the left-hand side by the value on the right-hand side and assigns the result back to the variable.

x /= 2; // Equivalent to x = x / 2; (divides the current value of "x" by 2 and assigns the result back to "x")

Bitwise AND assignment (&=): The bitwise AND assignment operator "&=" performs a bitwise AND operation between the value on the left-hand side and the value on the right-hand side. It then assigns the result back to the left-hand side variable.

x &= 3; // Binary: 0011 // After bitwise AND assignment: x = 1 (Binary: 0001)

Bitwise OR assignment (|=): The bitwise OR assignment operator "|=" performs a bitwise OR operation between the value on the left-hand side and the value on the right-hand side. It then assigns the result back to the left-hand side variable.

x |= 3; // Binary: 0011 // After bitwise OR assignment: x = 7 (Binary: 0111)

Bitwise XOR assignment (^=): The bitwise XOR assignment operator "^=" performs a bitwise XOR operation between the value on the left-hand side and the value on the right-hand side. It then assigns the result back to the left-hand side variable.

x ^= 3; // Binary: 0011 // After bitwise XOR assignment: x = 6 (Binary: 0110)

Left shift assignment (<<=): The left shift assignment operator "<<=" shifts the bits of the value on the left-hand side to the left by the number of positions specified by the value on the right-hand side. It then assigns the result back to the left-hand side variable.

x <<= 2; // Binary: 010100 (Shifted left by 2 positions) // After left shift assignment: x = 20 (Binary: 10100)

Right shift assignment (>>=): The right shift assignment operator ">>=" shifts the bits of the value on the left-hand side to the right by the number of positions specified by the value on the right-hand side. It then assigns the result back to the left-hand side variable.

x >>= 2; // Binary: 101 (Shifted right by 2 positions) // After right shift assignment: x = 5 (Binary: 101)

Conclusion The assignment operator in C, denoted by the equals sign (=), is used to assign a value to a variable. It is a fundamental operation that allows programmers to store data in variables for further use in their code. In addition to the simple assignment operator, C provides compound assignment operators that combine arithmetic or bitwise operations with assignment, allowing for concise and efficient code.

FAQs related to Assignment Operator in C

Q1. Can I assign a value of one data type to a variable of another data type? In most cases, assigning a value of one data type to a variable of another data type will result in a warning or error from the compiler. It is generally recommended to assign values of compatible data types to variables.

Q2. What is the difference between the assignment operator (=) and the comparison operator (==)? The assignment operator (=) is used to assign a value to a variable, while the comparison operator (==) is used to check if two values are equal. It is important not to confuse these two operators.

Q3. Can I use multiple assignment operators in a single statement? No, it is not possible to use multiple assignment operators in a single statement. Each assignment operator should be used separately for assigning values to different variables.

Q4. Are there any limitations on the right-hand side value of the assignment operator? The right-hand side value of the assignment operator should be compatible with the data type of the left-hand side variable. If the data types are not compatible, it may lead to unexpected behavior or compiler errors.

Q5. Can I assign the result of an expression to a variable using the assignment operator? Yes, it is possible to assign the result of an expression to a variable using the assignment operator. For example, x = y + z; assigns the sum of y and z to the variable x.

Q6. What happens if I assign a value to an uninitialized variable? Assigning a value to an uninitialized variable will initialize it with the assigned value. However, it is considered good practice to explicitly initialize variables before using them to avoid potential bugs or unintended behavior.

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21.12 — Overloading the assignment operator

The copy assignment operator (operator=) is used to copy values from one object to another already existing object .

Related content

As of C++11, C++ also supports “Move assignment”. We discuss move assignment in lesson 22.3 -- Move constructors and move assignment .

Copy assignment vs Copy constructor

The purpose of the copy constructor and the copy assignment operator are almost equivalent -- both copy one object to another. However, the copy constructor initializes new objects, whereas the assignment operator replaces the contents of existing objects.

The difference between the copy constructor and the copy assignment operator causes a lot of confusion for new programmers, but it’s really not all that difficult. Summarizing:

• If a new object has to be created before the copying can occur, the copy constructor is used (note: this includes passing or returning objects by value).
• If a new object does not have to be created before the copying can occur, the assignment operator is used.

Overloading the assignment operator

Overloading the copy assignment operator (operator=) is fairly straightforward, with one specific caveat that we’ll get to. The copy assignment operator must be overloaded as a member function.

This prints:

This should all be pretty straightforward by now. Our overloaded operator= returns *this, so that we can chain multiple assignments together:

Issues due to self-assignment

Here’s where things start to get a little more interesting. C++ allows self-assignment:

This will call f1.operator=(f1), and under the simplistic implementation above, all of the members will be assigned to themselves. In this particular example, the self-assignment causes each member to be assigned to itself, which has no overall impact, other than wasting time. In most cases, a self-assignment doesn’t need to do anything at all!

However, in cases where an assignment operator needs to dynamically assign memory, self-assignment can actually be dangerous:

First, run the program as it is. You’ll see that the program prints “Alex” as it should.

Now run the following program:

You’ll probably get garbage output. What happened?

Consider what happens in the overloaded operator= when the implicit object AND the passed in parameter (str) are both variable alex. In this case, m_data is the same as str.m_data. The first thing that happens is that the function checks to see if the implicit object already has a string. If so, it needs to delete it, so we don’t end up with a memory leak. In this case, m_data is allocated, so the function deletes m_data. But because str is the same as *this, the string that we wanted to copy has been deleted and m_data (and str.m_data) are dangling.

Later on, we allocate new memory to m_data (and str.m_data). So when we subsequently copy the data from str.m_data into m_data, we’re copying garbage, because str.m_data was never initialized.

Detecting and handling self-assignment

Fortunately, we can detect when self-assignment occurs. Here’s an updated implementation of our overloaded operator= for the MyString class:

By checking if the address of our implicit object is the same as the address of the object being passed in as a parameter, we can have our assignment operator just return immediately without doing any other work.

Because this is just a pointer comparison, it should be fast, and does not require operator== to be overloaded.

When not to handle self-assignment

Typically the self-assignment check is skipped for copy constructors. Because the object being copy constructed is newly created, the only case where the newly created object can be equal to the object being copied is when you try to initialize a newly defined object with itself:

In such cases, your compiler should warn you that c is an uninitialized variable.

Second, the self-assignment check may be omitted in classes that can naturally handle self-assignment. Consider this Fraction class assignment operator that has a self-assignment guard:

If the self-assignment guard did not exist, this function would still operate correctly during a self-assignment (because all of the operations done by the function can handle self-assignment properly).

Because self-assignment is a rare event, some prominent C++ gurus recommend omitting the self-assignment guard even in classes that would benefit from it. We do not recommend this, as we believe it’s a better practice to code defensively and then selectively optimize later.

The copy and swap idiom

A better way to handle self-assignment issues is via what’s called the copy and swap idiom. There’s a great writeup of how this idiom works on Stack Overflow .

The implicit copy assignment operator

Unlike other operators, the compiler will provide an implicit public copy assignment operator for your class if you do not provide a user-defined one. This assignment operator does memberwise assignment (which is essentially the same as the memberwise initialization that default copy constructors do).

Just like other constructors and operators, you can prevent assignments from being made by making your copy assignment operator private or using the delete keyword:

Note that if your class has const members, the compiler will instead define the implicit operator= as deleted. This is because const members can’t be assigned, so the compiler will assume your class should not be assignable.

If you want a class with const members to be assignable (for all members that aren’t const), you will need to explicitly overload operator= and manually assign each non-const member.

• <cassert> (assert.h)
• <cctype> (ctype.h)
• <cerrno> (errno.h)
• C++11 <cfenv> (fenv.h)
• <cfloat> (float.h)
• C++11 <cinttypes> (inttypes.h)
• <ciso646> (iso646.h)
• <climits> (limits.h)
• <clocale> (locale.h)
• <cmath> (math.h)
• <csetjmp> (setjmp.h)
• <csignal> (signal.h)
• <cstdarg> (stdarg.h)
• C++11 <cstdbool> (stdbool.h)
• <cstddef> (stddef.h)
• C++11 <cstdint> (stdint.h)
• <cstdio> (stdio.h)
• <cstdlib> (stdlib.h)
• <cstring> (string.h)
• C++11 <ctgmath> (tgmath.h)
• <ctime> (time.h)
• C++11 <cuchar> (uchar.h)
• <cwchar> (wchar.h)
• <cwctype> (wctype.h)

Containers:

• C++11 <array>
• <deque>
• C++11 <forward_list>
• <list>
• <map>
• <queue>
• <set>
• <stack>
• C++11 <unordered_map>
• C++11 <unordered_set>
• <vector>

Input/Output:

• <fstream>
• <iomanip>
• <ios>
• <iosfwd>
• <iostream>
• <istream>
• <ostream>
• <sstream>
• <streambuf>

Multi-threading:

• C++11 <atomic>
• C++11 <condition_variable>
• C++11 <future>
• C++11 <mutex>
• C++11 <thread>
• <algorithm>
• <bitset>
• C++11 <chrono>
• C++11 <codecvt>
• <complex>
• <exception>
• <functional>
• C++11 <initializer_list>
• <iterator>
• <limits>
• <locale>
• <memory>
• <new>
• <numeric>
• C++11 <random>
• C++11 <ratio>
• C++11 <regex>
• <stdexcept>
• <string>
• C++11 <system_error>
• C++11 <tuple>
• C++11 <type_traits>
• C++11 <typeindex>
• <typeinfo>
• <utility>
• <valarray>

class templates

• basic_string
• char_traits
• C++11 u16string
• C++11 u32string
• C++11 stold
• C++11 stoll
• C++11 stoul
• C++11 stoull
• C++11 to_string
• C++11 to_wstring
• string::~string
• string::string

member functions

• string::append
• string::assign
• C++11 string::back
• string::begin
• string::c_str
• string::capacity
• C++11 string::cbegin
• C++11 string::cend
• string::clear
• string::compare
• string::copy
• C++11 string::crbegin
• C++11 string::crend
• string::data
• string::empty
• string::end
• string::erase
• string::find
• string::find_first_not_of
• string::find_first_of
• string::find_last_not_of
• string::find_last_of
• C++11 string::front
• string::get_allocator
• string::insert
• string::length
• string::max_size
• string::operator[]
• string::operator+=
• string::operator=
• C++11 string::pop_back
• string::push_back
• string::rbegin
• string::rend
• string::replace
• string::reserve
• string::resize
• string::rfind
• C++11 string::shrink_to_fit
• string::size
• string::substr
• string::swap

member constants

• string::npos

non-member overloads

• getline (string)
• operator+ (string)
• operator<< (string)
• >/" title="operator>> (string)"> operator>> (string)
• relational operators (string)
• swap (string)

std:: string ::operator=

Return value, iterator validity, exception safety.

• Design Pattern
• Interview Q

C Control Statements

C functions, c dynamic memory, c structure union, c file handling, c preprocessor, c command line, c programming test, c interview.

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C Syntax Explained: From Variables To Functions

Unearth the secret intricacies of C in our comprehensive guide. We journey from understanding the fundamental syntax, making sense of arrays and strings, delving into operators and functions, and exploring advanced techniques with real-world applications.

💡 KEY INSIGHTS

• Pointer arithmetic in C is based on the data type size the pointer points to, making it a crucial concept for efficient memory manipulation and array operations.
• The article emphasizes the importance of the const keyword in C for declaring constants, ensuring safety against unintentional modifications and enhancing code reliability.
• Function pointers in C, which point to functions instead of data types, are highlighted for their utility in passing functions as arguments and creating function arrays.
• The guide underscores the difference between structures and unions in memory allocation, with structures allocating separate storage for each member, while unions use shared storage for all.

C is a foundational programming language that has influenced many modern languages we use today. Its syntax forms the bedrock for understanding more complex languages and systems. As you navigate through this article, you'll gain a deeper appreciation for the intricacies and elegance of C's structure. Happy coding!

Basic Data Types

Variables and constants, control structures, arrays and strings, structures and unions, file handling, frequently asked questions, integer types, floating-point types, character type, derived data types.

Explore the world of C's basic data types. This section offers a succinct overview of the primary data types in C, complete with code samples and descriptions. Whether you're a novice or simply revisiting the topic, this guide ensures you grasp the essentials of C programming.

In C, integers are whole numbers that can have both zero, positive, and negative values but no decimal values. The int keyword is used to declare integer variables. Depending on the architecture, an integer can be 2 or 4 bytes.

Floating-point types represent numbers with decimal points. C offers three types for floating-point numbers: float , double , and long double . The precision and storage of these types can vary based on the machine.

The character type is used to store a single character. The keyword used is char . Each character occupies 1 byte of memory in C. Characters are typically stored in ASCII codes.

The void type specifies that no value is available. It is used in functions to indicate that the function does not return any value.

Apart from the basic data types, C supports several derived data types like arrays, pointers, structures, and unions. These types are derived from the basic data types and allow for more complex data structures. For instance, an array can store multiple values of the same type.

Defining Variables

Variable initialization, constants and literals, the const keyword, the #define preprocessor.

Explore the nuances of variables and constants in C. This section delves into the declaration, initialization, and usage of variables, as well as the distinction between variables and constants. Grasp the essence of data storage and manipulation in C programming.

In C, variables are memory locations used to store data. To use a variable, you must first declare its type and name. The variable name should be relevant to its purpose in the program.

Variables are the named placeholders that capture the essence of programming, storing our data's soul.

Initialization refers to assigning a value to a variable at the time of declaration. It ensures that the variable has a defined value before it's used in the program.

Constants are values that remain unchanged throughout the program. A literal is a constant value used in the program, like numbers, characters, and strings. For example, 5 , 'a' , and "Hello" are literals.

The const keyword in C is used to declare a variable as constant, meaning its value cannot be changed after initialization. It provides a level of safety against unintentional changes.

Another way to define constants in C is using the #define preprocessor directive. It replaces the defined constant with its value during compilation.

Arithmetic Operators

Relational operators, logical operators, assignment operators, bitwise operators, special operators.

Unravel the intricacies of operators in C. Operators are symbols that perform operations on variables and values. From basic arithmetic to complex bitwise manipulations, this section provides a comprehensive overview of the different operators available in C.

Arithmetic operators are used to perform mathematical operations. Common ones include addition ( + ), subtraction ( - ), multiplication ( * ), division ( / ), and modulus ( % ).

Relational operators are used to compare two values. They include equals to ( == ), not equals to ( != ), greater than ( > ), less than ( < ), greater than or equal to ( >= ), and less than or equal to ( <= ).

Logical operators are used to determine the logic between variables or values. The primary ones are AND ( && ), OR ( || ), and NOT ( ! ).

Assignment operators are used to assign values to variables. The basic assignment operator is = . There are also compound assignment operators like += , -= , *= , and /= .

Bitwise operators act on individual bits of numbers. They include bitwise AND ( & ), OR ( | ), XOR ( ^ ), NOT ( ~ ), left shift ( << ), and right shift ( >> ).

C also has special operators like the comma operator ( , ), sizeof operator, pointer operators ( * and & ), and member selection operators ( . and -> ).

Conditional Statements

Looping structures, jump statements, switch case.

Delve into the control structures of C. These structures guide the flow of execution in a program, facilitating decisions, repetitions, and jumps in code. This section will clarify the various control structures and their uses in C programming.

Conditional statements allow the program to make decisions. The primary conditional statements in C are if , if-else , and else if . They evaluate a condition and execute a block of code based on the result.

Looping structures enable the execution of a block of code multiple times. The primary loops in C are for , while , and do-while . They repeat a block of code as long as a condition is true.

Jump statements allow the program to jump to a different part of the code. The primary jump statements in C are break , continue , and goto . While break and continue are used within loops, goto can jump to any part of the code.

The switch case structure allows a variable to be tested for equality against multiple values. Each value is called a case, and the variable is checked against each case.

Function Basics

• Function Declaration and Definition

Function Call

Return types and arguments, scope of variables, recursive functions.

Functions serve as the building blocks of a C program, enabling modular code that is both reusable and organized. This section will lead you through the various facets of functions, from their fundamental structure to more intricate topics.

A function is a group of statements that together perform a specific task. It helps in modularizing the code and improving readability. Functions also enhance reusability and make the code more organized.

Function Declaration And Definition

Every function in C has a declaration and a definition . The declaration provides information about the function to the compiler, while the definition contains the actual code.

Once a function is defined, it can be called from another function, including the main function. A function call tells the program to execute the code within the function.

Functions can return values. The type of value a function returns is specified in its declaration and definition. Functions can also take arguments or parameters to operate on.

Variables in C have a scope , which determines where they can be accessed. Variables declared inside a function are local to that function, while variables declared outside are global.

A recursive function is one that calls itself. It's crucial to have a base case in recursive functions to prevent infinite loops.

Array Basics

Multidimensional arrays, string basics, string functions, character arrays vs strings.

Explore the intricacies of arrays and strings in C. These fundamental data structures allow for the storage and manipulation of collections of data. This section will delve into the various aspects of arrays and strings, from their basic structure to more advanced operations.

An array is a collection of elements of the same type, stored in contiguous memory locations. The elements can be accessed randomly by indexing into the array using an integer.

Multidimensional arrays are arrays of arrays. The most common type is the two-dimensional array, often used to represent matrices.

A string in C is an array of characters ending with a null character ( '\0' ). Strings are used to store text.

C provides a plethora of string functions in the string.h library, such as strcpy() , strlen() , and strcat() , which allow for efficient string manipulations.

While both character arrays and strings seem similar, the key difference is the null terminator. Strings always end with a null character, while character arrays do not necessarily have to. This distinction is crucial when working with C functions that expect strings.

Pointer Arithmetic

Pointers and arrays, pointers to pointers, function pointers, dynamic memory allocation.

Pointers are one of the most powerful and yet challenging concepts in C programming. This section will guide you through the nuances of pointers, from their basic understanding to advanced applications.

A pointer is a variable that stores the address of another variable. Pointers allow for direct memory access and manipulation, making them essential for dynamic memory allocation and array operations.

Pointer arithmetic involves operations like addition and subtraction on pointer variables. It's crucial to understand that pointer arithmetic is based on the size of the data type the pointer points to.

Arrays and pointers are closely related in C. The name of an array is a pointer to its first element, and array elements can be accessed using pointer arithmetic.

It's possible to have pointers to pointers in C. This concept is often used in scenarios like multi-dimensional arrays and dynamic data structures.

Function pointers are pointers that point to functions instead of data types. They can be used to pass functions as arguments and create arrays of functions.

Pointers play a crucial role in dynamic memory allocation . Functions like malloc() , calloc() , and free() are used to allocate and deallocate memory at runtime.

Defining Structures

Accessing structure members, structures and functions, defining unions, difference between structures and unions.

Explore the intricacies of structures and unions in C. These user-defined data types allow for the grouping of variables of different data types. While they may seem similar, they serve distinct purposes and have unique characteristics.

A structure is a user-defined data type that allows grouping of variables of different data types. It provides a way to store multiple items of mixed types under a single name.

Members of a structure can be accessed using the dot operator. Once a structure variable is defined, its members can be initialized and accessed as shown below.

Structures can be passed to functions as arguments. They can be passed by value or by reference. It's common to pass them by reference to avoid copying large structures.

A union is similar to a structure but with a key difference. In a union, all members share the same memory location. This means only one member can contain a value at any given time.

The primary difference between structures and unions is the way memory is allocated. In structures, each member has its own storage, whereas, in unions, all members use the same storage. This makes unions useful when variables aren't used at the same time.

Opening And Closing Files

Reading from files, writing to files, error handling in files.

This section will guide you through the essential operations like opening, reading, writing, and closing files. Learn how to efficiently manage data storage and retrieval with hands-on examples.

In C, the FILE pointer is used to handle files. To open a file, use the fopen() function, and to close it, use the fclose() function. Always ensure that a file is closed after operations to free up resources.

To read from a file, functions like fgetc() , fgets() , and fread() are available. These functions allow for reading single characters, strings, or blocks of data respectively.

Writing to files can be achieved using functions like fputc() , fputs() , and fwrite() . These allow for writing single characters, strings, or blocks of data.

When opening a file, you need to specify the mode . Common modes include "r" for reading, "w" for writing, "a" for appending, and "b" for binary mode. Combining modes, like "r+" allows for both reading and writing.

It's crucial to handle potential errors when working with files. Functions like ferror() and feof() help in detecting errors and end-of-file conditions, ensuring smooth file operations. Always check if a file has opened successfully before performing operations.

What is the difference between = and == in C?

= is an assignment operator used to assign a value to a variable. == is a relational operator used to compare two values for equality.

Why do we use the void keyword in function declarations?

The void keyword indicates that the function does not return any value. It can also be used in the function's parameter list to indicate that the function does not accept any arguments.

How are arrays and pointers related in C?

An array name is essentially a constant pointer to the first element of the array. Pointers can be used to access and manipulate array elements.

What is the significance of the & and * operators in C?

The & operator is used to get the address of a variable, while the * operator is used to dereference a pointer, i.e., to access the value stored at the address pointed to by the pointer.

Why is it recommended to use curly braces { } even for single-statement blocks in control structures?

Using curly braces for single-statement blocks enhances code readability and reduces the risk of logic errors, especially when modifications are made to the code later on.

What is the difference between ++i and i++ ?

Both are increment operators. ++i (pre-increment) increments the value of i before its current value is used in an expression, while i++ (post-increment) uses the current value of i in an expression and then increments it.

How can I read a string with spaces using the scanf function?

The scanf function typically stops reading input upon encountering whitespace. To read a string with spaces, you can use the %[^\n] format specifier, which reads until a newline character is encountered.

Which operator is used for assignment in C?

Continue learning with these c guides.

• What Is C Programming Memory Allocation
• What Is C Programming Device Drivers
• C Programming And Assembly Language: A Step-By-Step Approach
• What Is C Programming Low-Level Programming
• How To Use C Programming System Programming

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• C++ Data Types
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• C++ Pointers
• C++ Interview Questions
• C++ Programs
• C++ Cheatsheet
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• C++ Exception Handling
• C++ Memory Management
• Increment (++) and Decrement (--) Operator Overloading in C++
• C++ Ternary or Conditional Operator
• C++ Logical Operators
• C++ Relational Operators
• Types of Operator Overloading in C++
• How to Overload the Function Call Operator () in C++?
• Increment Operator Behavior When Passed as Function Parameters in C++
• How to Use the Not-Equal (!=) Operator in C++?
• Operators in C++
• Constants in C++
• C++ Comparison Operators
• Casting Operators in C++
• C++ sizeof Operator
• Typecast Operator Overloading in C++
• C++ Program For Iterative Quick Sort
• How to Parse an Array of Objects in C++ Using RapidJson?
• C++ Increment and Decrement Operators
• C++ Arithmetic Operators
• How to Lock Window Resize C++ sfml?

C++ Assignment Operator Overloading

Prerequisite: Operator Overloading

The assignment operator,”=”, is the operator used for Assignment. It copies the right value into the left value. Assignment Operators are predefined to operate only on built-in Data types.

• Assignment operator overloading is binary operator overloading.
• Overloading assignment operator in C++ copies all values of one object to another object.
• Only a non-static member function should be used to overload the assignment operator.

We can’t directly use the Assignment Operator on objects. The simple explanation for this is that the Assignment Operator is predefined to operate only on built-in Data types. As the class and objects are user-defined data types, so the compiler generates an error.

here, a and b are of type integer, which is a built-in data type. Assignment Operator can be used directly on built-in data types.

c1 and c2 are variables of type “class C”. Here compiler will generate an error as we are trying to use an Assignment Operator on user-defined data types.

The above example can be done by implementing methods or functions inside the class, but we choose operator overloading instead. The reason for this is, operator overloading gives the functionality to use the operator directly which makes code easy to understand, and even code size decreases because of it. Also, operator overloading does not affect the normal working of the operator but provides extra functionality to it.

Now, if the user wants to use the assignment operator “=” to assign the value of the class variable to another class variable then the user has to redefine the meaning of the assignment operator “=”.  Redefining the meaning of operators really does not change their original meaning, instead, they have been given additional meaning along with their existing ones.

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