Operators

Introduction

In the previous lessons, you learned about data types and type conversion. Now that you know how to store different kinds of data, the next step is to perform operations on that data. Programs need to add numbers, calculate prices, compare values, check conditions, update scores, and make decisions. To perform these tasks, C++ provides operators.

Operators are among the most frequently used features in programming because almost every program performs calculations, comparisons, assignments, or logical evaluations.

What is an Operator?

An operator is a symbol that performs a specific operation on one or more values or expressions called operands.

10 + 20

10      → Operand
+       → Operator
20      → Operand

Result  → 30

Why Do We Need Operators?

Real-World Analogy & Components of an Expression

Imagine a calculator. When you enter 5 + 3, the calculator uses the + symbol to perform addition and produces the result 8. C++ uses operators in a similar way to perform different kinds of operations.

Consider the expression total = marks + bonus;. It contains operands, operators, and a result that is assigned to a variable.

total = marks + bonus;

marks      → Operand
+          → Arithmetic Operator
bonus      → Operand
=          → Assignment Operator
total      → Receives the Result

Types of Operators

C++ provides many categories of operators. This lesson focuses on the most commonly used operators for beginners.

1. Arithmetic Operators

Arithmetic operators perform mathematical calculations on numeric operands.

#include <iostream>

int main()
{
    int a = 20;
    int b = 10;

    std::cout << "Addition : " << a + b << std::endl;
    std::cout << "Subtraction : " << a - b << std::endl;
    std::cout << "Multiplication : " << a * b << std::endl;
    std::cout << "Division : " << a / b << std::endl;
    std::cout << "Remainder : " << a % b;

    return 0;
}

Addition : 30
Subtraction : 10
Multiplication : 200
Division : 2
Remainder : 0

std::cout << 5 / 2;      // 2
std::cout << 5.0 / 2;    // 2.5

2. Assignment Operator

The assignment operator = stores a value in an object such as a variable. The expression on the right side is evaluated, and the resulting value is assigned to the variable on the left side.

#include <iostream>

int main()
{
    int number;

    number = 50;

    std::cout << number;

    return 0;
}

50

3. Relational Operators

Relational operators compare two operands. The result of a relational expression is a Boolean value: true or false.

#include <iostream>

int main()
{
    int a = 20;
    int b = 10;

    std::cout << (a > b);

    return 0;
}

1

4. Logical Operators

Logical operators are used with conditions. They can combine multiple conditions or invert a condition.

#include <iostream>

int main()
{
    int age = 20;

    std::cout << (age >= 18 && age <= 60);

    return 0;
}

age >= 18      → true
age <= 60      → true

true && true   → true

Output         → 1

5. Increment and Decrement Operators

The increment and decrement operators increase or decrease a modifiable value by one.

#include <iostream>

int main()
{
    int count = 10;

    count++;

    std::cout << count;

    return 0;
}

11

int a = 10;
int b = 10;

int x = ++a;   // a becomes 11, then x receives 11
int y = b++;   // y receives 10, then b becomes 11

Memory Representation of Increment

Conceptually, incrementing a variable changes its stored value. The variable itself continues to refer to the same object.

Before:

int score = 50;

score
┌──────────────┐
│      50      │
└──────────────┘

After:

score++;

score
┌──────────────┐
│      51      │
└──────────────┘

The stored value changes from 50 to 51.

Operator Precedence

When an expression contains multiple operators, precedence and associativity determine how the expression is grouped. For example, multiplication has higher precedence than addition.

10 + 5 * 2

Step 1:
5 * 2 = 10

Step 2:
10 + 10 = 20

Result: 20

int result1 = 10 + 5 * 2;      // 20
int result2 = (10 + 5) * 2;    // 30

Program Execution Flow

Real-World Applications

Common Beginner Mistakes

// Assignment
age = 18;

// Comparison
age == 18

if (divisor != 0)
{
    int result = number / divisor;
}

Best Practices

Frequently Asked Questions

Key Takeaways

Summary

Operators are essential building blocks of C++ programming because they allow programs to calculate values, compare data, evaluate conditions, assign results, and update variables. Arithmetic, assignment, relational, logical, increment, and decrement operators appear throughout C++ programs. Understanding how these operators behave, including integer division, short-circuit evaluation, and operator precedence, provides the foundation for writing correct and readable expressions.