The if statement tests the condition. It executes the if block if a condition is true.

Syntax

if(condition){  
//code to be executed  
}

Here, if statement may be a single statement or a compound statement enclosed in curly braces (that is, a block).

The statements get executed only when the given condition is true. If the condition is false then the statements inside if statement body is completely ignored.

Kotlin - if statement example

package net.javaguides.kotlin

fun main(args: Array < String > ) {

    var x = 10;
    var y = 20;
    if (x < y) {
        System.out.println("x is less than y");
    }
    x = x * 2;
    if (x == y) {
        System.out.println("x now equal to y");
    }
    x = x * 2;
    if (x > y) {
        System.out.println("x now greater than y");
    }
    // this won't display anything
    if (x == y) {
        System.out.println("you won't see this");
    }

}

Output:

x is less than y
x now equal to y
x now greater than y