Comparison operators in Kotlin

Introduction

Comparison operators help us check if values are equal or which one is bigger or smaller. This is useful to make decisions in programs.

Checking if a user entered the correct password

Comparing ages to see who is older

Finding out if a number is positive or negative

Deciding if a score is high enough to pass

Sorting items by size or price

Syntax

Kotlin

a == b  // equals
 a != b  // not equals
 a > b   // greater than
 a < b   // less than
 a >= b  // greater than or equal to
 a <= b  // less than or equal to

Use double equals (==) to check if two values are the same.

Use != to check if two values are different.

Examples

This checks if x and y are equal. They are not, so it prints false.

Kotlin

val x = 5
val y = 10
println(x == y)  // false

This checks if a and b are different. They are the same, so it prints false.

Kotlin

val a = 7
val b = 7
println(a != b)  // false

This checks if age is at least 18. It is, so it prints true.

Kotlin

val age = 18
println(age >= 18)  // true

This checks if score is less than 50. It is not, so it prints false.

Kotlin

val score = 75
println(score < 50)  // false

Sample Program

This program checks if the temperature is hot, cold, or exactly 30 degrees using comparison operators.

Kotlin

fun main() {
    val temperature = 30
    val isHot = temperature > 25
    val isCold = temperature < 15
    println("Is it hot? $isHot")
    println("Is it cold? $isCold")
    println("Is temperature exactly 30? ${temperature == 30}")
}

Important Notes

Comparison operators return a Boolean value: true or false.

Use parentheses {} inside strings to show the result of comparisons.

Summary

Comparison operators help compare two values.

They return true or false depending on the comparison.

Common operators: ==, !=, >, <, >=, <=.