C++Assignment OperatorsEqual Operator

Basic Assignment Operator (=) in C++

The assignment operator (=) in C++ is one of the most fundamental operators. It is used to assign the value of the right-hand side expression to the left-hand side variable.

Purpose

  • Stores a value in a variable.
  • Can be used with literals, variables, or expressions.
  • Enables initialization and value updates throughout the program.

Syntax

variable = value;
  • variable: A declared identifier (must be declared before assignment).
  • value: A literal, expression, or another variable.

Example 1: Basic Integer Assignment

assignment_int.cpp
int a;
a = 5;
std::cout << a;  // Output: 5

Explanation:

  • Variable a is assigned the value 5 using =.
  • That value is stored and printed.

Example 2: Initialization at Declaration

assignment_declaration.cpp
int age = 21;

Explanation:

  • This is known as inline initialization—declaring and assigning in a single step.

Example 3: Using Expressions

assignment_expression.cpp
int x = 10;
int y = 5;
int result = x + y;  // result = 15

Explanation:

  • The result of x + y is evaluated to 15 and assigned to result.

Example 4: Assignment with Different Data Types

Float Assignment

assignment_float.cpp
float pi = 3.14f;

Character Assignment

assignment_char.cpp
char letter = 'C';

Boolean Assignment

assignment_bool.cpp
bool isOnline = true;

Example 5: Updating a Variable

assignment_update.cpp
int count = 1;
count = count + 1;
std::cout << count;  // Output: 2

Explanation:

  • count + 1 is evaluated first → 2 is assigned to count.

Example 6: Chain Assignment

assignment_chain.cpp
int x, y, z;
x = y = z = 100;

Explanation:

  • Values are assigned right-to-left.
  • First, z = 100, then y = z, and finally x = y.

Important Notes

  • The assignment operator = is not a comparison.

    • x = 5 assigns.
    • x == 5 checks equality.

Practice Exercises

  1. Declare a variable radius and assign it 7.5.
  2. Assign a character 'A' to a variable and print it.
  3. Assign the sum of two integers into a third variable.
  4. Use chain assignment to assign 50 to a, b, and c.

Common Mistakes

MistakeExplanation
int x; x + 5;The result is unused; assignment is missing.
x == 10;This checks equality instead of assigning.

Summary

  • The = operator assigns the right-hand value to the left-hand variable.
  • Supports all primitive types (int, float, char, bool, etc.).
  • Enables chaining and inline initialization.
  • Critical for program logic, variable updates, and calculations.
Logical NOTAddition Assignment