Kotlin program to find the sum of all numbers of an array

Introduction :

Kotlin program to find the sum of all numbers in an array. One number array is given and we need to find out the sum of its numbers.

Method 1: Using sum() :

Array in kotlin provides one method called sum that returns the sum of all elements of an array. Just call this method sum() to an array :

fun main() {
    val givenArray = intArrayOf(1,2,3,4,5,6,7,8,9)

    println(givenArray.sum())
}

It prints 45.

Method 2: Using fold :

We can also fold the array elements to find the sum of all values :

fun main() {
    val givenArray = intArrayOf(1,2,3,4,5,6,7,8,9)

    println(givenArray.fold(0){acc, e -> acc + e})
}

The accumulator acc adds the values of all elements of the array.

Method 3: Using forEach :

Iterate through the array and add each number to a sum variable :

fun main() {
    val givenArray = intArrayOf(1, 2, 3, 4, 5, 6, 7, 8, 9)

    var sum = 0
    givenArray.forEach { sum += it }

    println(sum)
}

You can also use one normal for loop.

Method 4: Using reduce :

reduce works like fold. It accumulates all values starting from the first element from left to right :

fun main() {
    val givenArray = intArrayOf(1, 2, 3, 4, 5, 6, 7, 8, 9)

    println(givenArray.reduce { sum, e -> sum + e })
}

It will print the sum.

Example of all methods :

fun main() {
    val givenArray = intArrayOf(1, 2, 3, 4, 5, 6, 7, 8, 9)

    println(givenArray.sum())
    println(givenArray.fold(0){acc, e -> acc + e})

    var sum = 0
    givenArray.forEach { sum += it }
    println(sum)

    println(givenArray.reduce { s, e -> s + e })
}

Kotlin sum array numbers

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