Control flow elements

In Kotlin, control flow elements are expressions. This is different from Java, in which they are statements. Statements just specify the flow of a program, and don't return any values. This section will cover the following control flow elements:

• The if { ... } else { ... } expression
• The when { ... } expression

The if { ... } else { ... } expression

In Kotlin, the if control flow element can be used in the same way as it is used in Java. The following example demonstrates the use of if as a usual statement:

fun ifStatement() {
    val a = 4
    if (a < 5) {
        println(a)
    }
}

If you are using the if { ... } else { ... } control flow element as an expression, you have to declare the else...