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

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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