Relational operators in C

Introduction

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

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.

Deciding if a score is high enough to pass a test.

Stopping a loop when a condition is no longer true.

Syntax

C

expression1 operator expression2

expression1 and expression2 are values or variables you want to compare.

operator can be one of: ==, !=, >, <, >=, <=.

Examples

Checks if a is equal to b.

C

if (a == b) { /* code */ }

Checks if x is not equal to y.

C

if (x != y) { /* code */ }

Checks if score is greater than or equal to 50.

C

if (score >= 50) { /* code */ }

Checks if age is less than 18.

C

if (age < 18) { /* code */ }

Sample Program

This program compares two numbers using relational operators and prints messages based on the comparisons.

C

#include <stdio.h>

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

    if (a < b) {
        printf("a is less than b\n");
    }

    if (a != b) {
        printf("a is not equal to b\n");
    }

    if (b >= 20) {
        printf("b is greater than or equal to 20\n");
    }

    if (a == 10) {
        printf("a is equal to 10\n");
    }

    return 0;
}

Important Notes

Relational operators always return 1 (true) or 0 (false) in C.

Use double equals (==) to check equality, not a single equals (=) which is for assignment.

Be careful with operator precedence when combining multiple conditions.

Summary

Relational operators compare two values and return true or false.

They are useful for making decisions in your program.

Common operators include ==, !=, >, <, >=, and <=.