# Java Program to Print Summation of Numbers

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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Java Foundationand Collections concepts with theFundamentals of Java and Java Collections Courseat a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more, please referComplete Interview Preparation Course.Output: 15

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

Output: -7

### Approach 1: Iteration in an Array

- Create a variable named sum and initialize it to 0.
- Traverse the array through a loop and add the value of each element into sum.
- 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