Relational operators in C++

Introduction

Relational operators help us compare two values to see how they relate to each other, like if one is bigger or smaller.

Checking if a number is greater than another to decide what to do next.

Comparing ages to see who is older.

Finding out if two values are equal before continuing a task.

Determining if a score is less than a passing mark.

Seeing if a temperature is within a safe range.

Syntax

C++

value1 < value2
value1 > value2
value1 <= value2
value1 >= value2
value1 == value2
value1 != value2

Use == to check if two values are equal, not = which assigns a value.

Relational operators return true or false (boolean values).

Examples

This checks if a is less than b. It is true because 5 is less than 10.

C++

int a = 5;
int b = 10;
bool result = a < b;  // true

This checks if x is equal to y. It is true because both are 7.

C++

int x = 7;
int y = 7;
bool result = x == y;  // true

This checks if m is not equal to n. It is true because 3 is not 8.

C++

int m = 3;
int n = 8;
bool result = m != n;  // true

Sample Program

This program compares two ages using relational operators and prints the results as 1 (true) or 0 (false).

C++

#include <iostream>
using namespace std;

int main() {
    int age1 = 20;
    int age2 = 25;

    cout << "Is age1 less than age2? " << (age1 < age2) << "\n";
    cout << "Is age1 equal to age2? " << (age1 == age2) << "\n";
    cout << "Is age1 not equal to age2? " << (age1 != age2) << "\n";

    return 0;
}

Important Notes

Relational operators always return a boolean value: true or false.

In C++, true prints as 1 and false prints as 0 when using cout.

Be careful to use == for comparison, not = which is for assignment.

Summary

Relational operators compare two values and return true or false.

They include <, >, <=, >=, ==, and !=.

Use them to make decisions based on how values relate to each other.