Given a number n, find GCD of its digits.

**Examples :**

Input : 345 Output : 1 GCD of 3, 4 and 5 is 1. Input : 2448 Output : 2 GCD of 2, 4, 4 and 8 is 2

We traverse the digits of number one by one using below loop

digit = n mod 10; n = n / 10;

While traversing digits, we keep track of current GCD and keep updating GCD by finding GCD of current digit with current GCD.

## C++

`// CPP program to find GCD of digits of a number ` `#include<iostream> ` `#include<algorithm> ` `using` `namespace` `std; ` ` ` `int` `digitGCD(` `int` `n) ` `{ ` ` ` `int` `gcd = 0; ` ` ` `while` `(n > 0) ` ` ` `{ ` ` ` `gcd = __gcd(n%10, gcd); ` ` ` ` ` `// If at point GCD becomes 1, ` ` ` `// return it ` ` ` `if` `(gcd == 1) ` ` ` `return` `1; ` ` ` ` ` `n = n/10; ` ` ` `} ` ` ` `return` `gcd; ` `} ` ` ` `// driver code ` `int` `main() ` `{ ` ` ` `long` `n = 2448; ` ` ` `cout << digitGCD(n); ` ` ` `return` `0; ` `} ` |

## Java

`// Java program to find GCD of digits of a number ` ` ` `class` `GFG ` `{ ` ` ` `// Recursive function to return gcd of a and b ` ` ` `static` `int` `__gcd(` `int` `a, ` `int` `b) ` ` ` `{ ` ` ` `return` `b == ` `0` `? a : __gcd(b, a % b); ` ` ` ` ` `} ` ` ` `static` `int` `digitGCD(` `int` `n) ` ` ` `{ ` ` ` `int` `gcd = ` `0` `; ` ` ` `while` `(n > ` `0` `) ` ` ` `{ ` ` ` `gcd = __gcd(n % ` `10` `, gcd); ` ` ` ` ` `// If at point GCD becomes 1, ` ` ` `// return it ` ` ` `if` `(gcd == ` `1` `) ` ` ` `return` `1` `; ` ` ` ` ` `n = n / ` `10` `; ` ` ` `} ` ` ` `return` `gcd; ` ` ` `} ` ` ` ` ` `// Driver code ` ` ` `public` `static` `void` `main (String[] args) ` ` ` `{ ` ` ` `int` `n = ` `2448` `; ` ` ` `System.out.print(digitGCD(n)); ` ` ` `} ` `} ` ` ` `// This code is contributed by Anant Agarwal. ` |

## Python3

`# Python program to find ` `# GCD of digits of a number ` ` ` `# Recursive function to return gcd of a and b ` `def` `__gcd(a,b): ` ` ` `return` `a ` `if` `(b` `=` `=` `0` `) ` `else` `__gcd(b, a ` `%` `b) ` ` ` `def` `digitGCD(n): ` ` ` ` ` `gcd ` `=` `0` ` ` `while` `(n > ` `0` `): ` ` ` ` ` `gcd ` `=` `__gcd(n ` `%` `10` `, gcd) ` ` ` ` ` `# If at point GCD becomes 1, ` ` ` `# return it ` ` ` `if` `(gcd ` `=` `=` `1` `): ` ` ` `return` `1` ` ` ` ` `n ` `=` `n ` `/` `/` `10` ` ` ` ` `return` `gcd ` ` ` `#Driver code ` `n ` `=` `2448` `print` `(digitGCD(n)) ` ` ` `# This code is contributed ` `# by Anant Agarwal. ` |

## C#

`// C# program to find GCD of ` `// digits of a number ` `using` `System; ` ` ` `class` `GFG { ` ` ` ` ` `// Recursive function to return ` ` ` `// gcd of a and b ` ` ` `static` `int` `__gcd(` `int` `a, ` `int` `b) ` ` ` `{ ` ` ` `return` `b == 0 ? a : __gcd(b, a % b); ` ` ` ` ` `} ` ` ` ` ` `static` `int` `digitGCD(` `int` `n) ` ` ` `{ ` ` ` `int` `gcd = 0; ` ` ` `while` `(n > 0) ` ` ` `{ ` ` ` `gcd = __gcd(n % 10, gcd); ` ` ` ` ` `// If at point GCD becomes 1, ` ` ` `// return it ` ` ` `if` `(gcd == 1) ` ` ` `return` `1; ` ` ` ` ` `n = n / 10; ` ` ` `} ` ` ` `return` `gcd; ` ` ` `} ` ` ` ` ` `// Driver code ` ` ` `public` `static` `void` `Main () ` ` ` `{ ` ` ` `int` `n = 2448; ` ` ` `Console.Write(digitGCD(n)); ` ` ` `} ` `} ` ` ` `// This code is contributed by Nitin Mittal. ` |

## PHP

`<?php ` `// PHP program to find GCD ` `// of digits of a number ` ` ` `// Recursive function to ` `// return gcd of a and b ` `function` `__gcd(` `$a` `,` `$b` `) ` `{ ` ` ` `return` `$b` `== 0 ? ` `$a` `: ` ` ` `__gcd(` `$b` `, ` `$a` `% ` `$b` `); ` ` ` `} ` ` ` `function` `digitGCD(` `$n` `) ` `{ ` ` ` `$gcd` `= 0; ` ` ` `while` `(` `$n` `> 0) ` ` ` `{ ` ` ` `$gcd` `= __gcd(` `$n` `% 10, ` `$gcd` `); ` ` ` ` ` `// If at point GCD ` ` ` `// becomes 1, return it ` ` ` `if` `(` `$gcd` `== 1) ` ` ` `return` `1; ` ` ` ` ` `$n` `= ` `$n` `/ 10; ` ` ` `} ` ` ` `return` `$gcd` `; ` `} ` ` ` `// Driver code ` `$n` `= 2448; ` `echo` `digitGCD(` `$n` `); ` ` ` `// This code is contributed by Sam007 ` `?> ` |

**Output :**

2

This article is contributed by **Dibyendu Roy Chaudhuri**. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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