# 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
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

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 ` `#include ` ` `  `// 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

 ` `

Output:

```14 25 20 11
```

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