# C# Program to Find Sum of Digits of a Number Using Recursion

• Last Updated : 22 Apr, 2022

Given a number, we need to find the sum of digits in the number using recursion. In C#, recursion is a process in which a function calls itself directly or indirectly and the corresponding function is known as a recursive function. It is used to solve problems easily like in this article using recursion we will find the sum of digits of a number.

Example

```Input: 456
Output: 15

Input: 123
Output: 6```

Approach:

To find the sum of digits of a number using recursion follow the following approach:

• We call the SumOfDigits function with the argument n.
• In function, the last digit is retrieved by n % 10.
• The function is recursively called with argument as n / 10.[i.e. n % 10 + SumOfDigit(n / 10)]
• The function is called recursively until the n > 0.

Example 1:

## C#

 `// C# program to find the sum of digits of a number``// using recursion``using` `System;` `class` `GFG{``    ` `// Method to check sum of digit using recursion``static` `int` `SumOfDigit(``int` `n)``{``    ` `    ``// If the n value is zero then we``    ``// return sum as 0.``    ``if` `(n == 0)``        ``return` `0;``        ` `    ``// Last digit + recursively calling n/10``    ``return``(n % 10 + SumOfDigit(n / 10));``}` `// Driver code``public` `static` `void` `Main()``{``    ``int` `n = 123;``    ``int` `ans = SumOfDigit(n);``    ` `    ``Console.Write(``"Sum = "` `+ ans);``}``}`
Output
`Sum = 6`

Example 2:

## C#

 `// C# program to find the sum of digits of a number``// using recursion``// Here, we take input from user``using` `System;` `class` `GFG{``    ` `// Method to check sum of digit using recursion``static` `int` `SumOfDigit(``int` `n)``{``    ` `    ``// If the n value is zero then we return sum as 0.``    ``if` `(n == 0)``        ``return` `0;``        ` `    ``// Last digit + recursively calling n/10``    ``return` `(n % 10 + SumOfDigit(n / 10));``}` `// Driver code``public` `static` `void` `Main()``{``    ``int` `number, res;``    ` `    ``// Taking input from user``    ``Console.WriteLine(``"Hi! Enter the Number: "``);``    ``number = ``int``.Parse(Console.ReadLine());``    ``res = SumOfDigit(number);``    ` `    ``// Displaying the output``    ``Console.WriteLine(``"Sum of Digits is {0}"``, res);``    ``Console.ReadLine();``}``}`

Output:

```Hi! Enter the Number:
12345
The Sum of Digits is 15```

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