# Java Program to Print Summation of Numbers

• Last Updated : 21 Oct, 2020

Given an array of integers, print the sum of all the elements in an array.

#### Examples:

Input: arr[] = {1,2,3,4,5}

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Output: 15

Input: arr[] = {2, 9, -10, -1, 5, -12}

Output: -7

### Approach 1: Iteration in an Array

1. Create a variable named sum and initialize it to 0.
2. Traverse the array through a loop and add the value of each element into sum.
3. Print sum as the answer.

Below is the implementation of the above approach.

## Java

 `// Java Program to print the sum ``// of all the elements in an array``class` `GFG {`` ` `    ``static` `int` `sumOfArray(``int` `arr[])``    ``{``        ``// initialise sum to 0``        ``int` `sum = ``0``;``       ` `        ``// iterate through the array using loop``        ``for` `(``int` `i = ``0``; i < arr.length; i++) {``            ``sum = sum + arr[i];``        ``}`` ` `        ``// return sum as the answer``        ``return` `sum;``    ``}`` ` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// print the sum``        ``int` `arr[] = { ``1``, ``2``, ``3``, ``4``, -``2``, ``5` `};``        ``System.out.println(``            ``"The sum of elements of given array is: "``            ``+ sumOfArray(arr));``    ``}``}`
Output
`The sum of elements of given array is: 13`

Time Complexity: O(N), where N is the size of array

### Approach 2: IntStream.of(arrayName).sum()

Inbuilt function IntStream.of(arrayName).sum() is used to sum all the elements in an integer array.

Syntax:

`IntStream.of(arrayName).sum();`

Below is the implementation of the above approach.

## Java

 `// Java Program to print the sum ``// of all the elements in an array`` ` `// import IntStream``import` `java.util.stream.IntStream;`` ` `class` `GFG {`` ` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// print the sum``        ``int` `arr[] = { ``1``, ``2``, ``3``, ``4``, -``2``, ``5` `};``        ``System.out.println(``            ``"The sum of elements of given array is: "``            ``+ IntStream.of(arr).sum());``    ``}``}`
Output
`The sum of elements of given array is: 13`

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