# Sum of consecutive two elements in a array

Given an array print sum of the pairwise consecutive elements.

Examples:

Input : 8, 5, 4, 3, 15, 20 Output : 13, 9, 7, 18, 35 Input : 5, 10, 15, 20 Output : 15, 25, 35

The solution is to traverse the array and saving the sum of consecutive numbers in the variable sum.

## C++

`// C++ program to print the` `// sum of the consecutive elements.` `#include <stdio.h>` `#include <stdlib.h>` `// Function to print pairwise sum` `void` `pairwiseSum(` `int` `arr[], ` `int` `n)` `{` ` ` `int` `sum = 0; ` ` ` `for` `(` `int` `i = 0; i < n - 1; i++)` ` ` `{` ` ` `// adding the alternate numbers` ` ` `sum = arr[i] + arr[i + 1];` ` ` `printf` `(` `" %d "` `, sum);` ` ` `}` `}` `// Driver function to test function` `int` `main()` `{` ` ` `int` `arr[] = {4, 10, 15, 5, 6};` ` ` `int` `n = ` `sizeof` `(arr) / ` `sizeof` `(arr[0]);` ` ` ` ` `pairwiseSum(arr, n);` ` ` `return` `0;` `}` |

## Java

`// Java program to print the` `// sum of the consecutive elements.` `class` `Arraysum {` ` ` ` ` `// Function to print Alternatesum` ` ` `static` `void` `pairwiseSum(` `int` `arr[], ` `int` `n)` ` ` `{` ` ` `int` `sum = ` `0` `;` ` ` `for` `(` `int` `i = ` `0` `; i + ` `1` `< n; i++)` ` ` `{` ` ` `// adding the alternate numbers` ` ` `sum = arr[i] + arr[i + ` `1` `];` ` ` `System.out.print(sum + ` `" "` `);` ` ` `}` ` ` `}` ` ` ` ` `/*driver function to test function*/` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` ` ` `int` `arr[] = {` `4` `, ` `10` `, ` `15` `, ` `5` `, ` `6` `};` ` ` `int` `n = arr.length;` ` ` `pairwiseSum(arr, n);` ` ` `}` `}` |

## Python3

`# Python3 program to print the` `# sum of the consecutive elements.` `# Function to print alternate sum` `def` `pairwiseSum(lst, n):` ` ` `sum` `=` `0` `;` ` ` `for` `i ` `in` `range` `(` `len` `(lst)` `-` `1` `):` ` ` ` ` `# adding the alternate numbers` ` ` `sum` `=` `lst[i] ` `+` `lst[i ` `+` `1` `]` ` ` `print` `(` `sum` `, end ` `=` `" "` `)` ` ` `# driver function to test function` `arr ` `=` `[` `4` `, ` `10` `, ` `15` `, ` `5` `, ` `6` `]` `size ` `=` `len` `(arr)` `pairwiseSum(arr, size)` |

## C#

`// C# program to print the` `// sum of the consecutive elements.` `using` `System;` `class` `Arraysum {` ` ` ` ` `// Function to print Alternatesum` ` ` `static` `void` `pairwiseSum(` `int` `[]arr, ` `int` `n)` ` ` `{` ` ` `int` `sum = 0;` ` ` `for` `(` `int` `i = 0; i + 1 < n; i++)` ` ` `{` ` ` `// adding the alternate numbers` ` ` `sum = arr[i] + arr[i + 1];` ` ` `Console.Write(sum + ` `" "` `);` ` ` `}` ` ` `}` ` ` ` ` `// Driver function` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` ` ` `int` `[]arr = {4, 10, 15, 5, 6};` ` ` `int` `n = arr.Length;` ` ` `pairwiseSum(arr, n);` ` ` `}` `}` `// This code is contributed by vt_m.` |

## PHP

`<?php` `// PHP program to print the` `// sum of the consecutive elements.` `// Function to print pairwise sum` `function` `pairwiseSum(` `$arr` `, ` `$n` `)` `{` ` ` `$sum` `= 0;` ` ` `for` `(` `$i` `= 0; ` `$i` `< ` `$n` `- 1; ` `$i` `++)` ` ` `{` ` ` ` ` `// adding the alternate numbers` ` ` `$sum` `= ` `$arr` `[` `$i` `] + ` `$arr` `[` `$i` `+ 1];` ` ` `echo` `$sum` `,` `" "` `;` ` ` `}` `}` ` ` `// Driver Code` ` ` `$arr` `= ` `array` `(4, 10, 15, 5, 6);` ` ` `$n` `= sizeof(` `$arr` `) ;` ` ` `pairwiseSum(` `$arr` `, ` `$n` `);` ` ` `// This code is contributed by ajit` `?>` |

## Javascript

`<script>` `// Javascript program to print the` `// sum of the consecutive elements.` `// Function to print Alternatesum` `function` `pairwiseSum(arr, n)` `{` ` ` `let sum = 0;` ` ` `for` `(let i = 0; i + 1 < n; i++)` ` ` `{` ` ` ` ` `// Adding the alternate numbers` ` ` `sum = arr[i] + arr[i + 1];` ` ` `document.write(sum + ` `" "` `);` ` ` `}` `}` `// Driver code` `let arr = [ 4, 10, 15, 5, 6 ];` `let n = arr.length;` `pairwiseSum(arr, n);` `// This code is contributed by divyesh072019` `</script>` |

**Output: **

14 25 20 11