Kotlin Increment Operator

In this tutorial, you shall learn about Increment operator in Kotlin, its syntax, and how to use Increment operator in programs, with examples.

Kotlin Increment

Kotlin Increment Operator takes a variable as operand and increments the value in variable by one.

++ symbol is used for Increment Operator.

There are two types of increment operations based on the position of operand for the operator.

Pre-increment
Post-increment

Syntax

The syntax for Increment Operator is

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//pre-increment
++operand

//post-increment
operand++

The operands could be of any numeric datatype.

For Pre-increment operation, first the value in the variable is incremented, and then the value is substituted in the expression or current statement.

For Post-increment operation, first the current statement is executed, and then the value in the variable is incremented.

Examples

1. Increment a variable

In the following example, we take an integer value in a, and increment its value using Increment Operator.

Main.kt

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fun main() {
    var a = 5
    a++
    println("a : $a")
}

Output

a : 6

2. Increment a decimal value

In the following example, we take a decimal value in a, and increment its value using Increment Operator.

Main.kt

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fun main() {
    var a = 5.748
    a++
    println("a : $a")
}

Output

a : 6.748

3. Pre-increment

In the previous examples, we have seen post-increment operation. But in this example, we will see how a pre-increment operation works.

In the following example, we take an integer value in a, and pre-increment its value using Increment Operator.

Main.kt

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fun main() {
    var a = 5
    var result = ++a * 4
    println("a : $result")
}

Output

a : 24

The value in a is incremented by 1, and then that value of a is substituted in the expression.

Now, let us take the same example, but with post-increment operation.

Main.kt

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fun main() {
    var a = 5
    var result = a++ * 4
    println("a : $result")
}

Output

a : 20

First the expression a * 4 is evaluated, and then the increment of a happens. If you print the value of a after the third line, then you would observe that the value in a is incremented.

Conclusion

In this Kotlin Tutorial, we learned how to use Increment Operator to increase the value in a variable by one.

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