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 })
}
