The if statement

Learn how to check a condition with if.

The if statement

The if statement runs a block when a condition is true. The condition goes in parentheses; the block is wrapped in curly braces.

val age = 18
if (age >= 18) {
    println("Adult")
}

The condition is a Boolean expression: true or false. If true, the block runs; if false, it is skipped. Comparison operators (>, <, ==, >=, <=) were covered earlier.

For single-line blocks the braces are optional, but recommended for readability.

Comparison and logical operators

Conditions use comparison operators. These were covered earlier but let's quickly recap.

5 > 3       // true
5 < 3       // false
5 == 5      // true
5 != 3      // true
5 >= 5      // true
5 <= 4      // false

== checks value equality, != checks inequality. For Strings, == compares content too (unlike Java).

Logical operators && (and), || (or), ! (not) combine conditions: age >= 18 && age < 65.

Exercise Check the age

Write a fun main(). Assign 20 to val age. Use if (age >= 18) to print println("Adult").

Show example solution

fun main() {
    val age = 20
    if (age >= 18) {
        println("Adult")
    }
}

Test yourself

When does if (age >= 18) run?
- When age is below 18
- When age is 18 or above
- Always
- Never
Show answer

When age is 18 or above — >= 18 covers 18 and above.

Complete the comparison operator

val adult = age ____ 18

Show answer

val adult = age >= 18

Match the conditions

age >= 18

18 or above
age < 18

Below 18
age == 18

Exactly 18
age != 18

Not 18

Next lesson: else and else if

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies