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Program to find the last digit of X in base Y
• Last Updated : 06 Apr, 2021

Given a positive integer X and Y, the task is to find the last digit of X in the given base Y.

Examples:

```Input: X = 10, Y = 7
Output: 3
10 is 13 in base 9 with last digit 3

Input: X = 55, Y = 3
Output: 1
55 is 3 in base 601 with last digit 1```

Approach:

• When we try to convert X into the base Y
• We repeatedly divide X by base Y and store the remainder.
• So final result comprises of the remainders in the order of division steps.
• Lets say the remainder of division step 1 is p, step 2 is q, step 3 is r
• Then the resultant number in base Y will be rqp
• And the last digit will be p
• Therefore, we just need to find the first remainder of X when divided by Y to get the last digit in X in base Y.

`last digit = X % Y`

Below is the implementation of the above approach:

## C++

 `// C++ Program to find``// the last digit of X in base Y` `#include ``using` `namespace` `std;` `// Function to find the last``// digit of X in base Y``void` `last_digit(``int` `X, ``int` `Y)``{``    ``cout << X % Y;``}` `// Driver code``int` `main()``{``    ``int` `X = 55, Y = 3;``    ``last_digit(X, Y);``    ``return` `0;``}`

## Java

 `// Java Program to find``// the last digit of X in base Y``class` `GFG``{` `// Function to find the last``// digit of X in base Y``static` `void` `last_digit(``int` `X, ``int` `Y)``{``    ``System.out.print(X % Y);``}` `// Driver code``public` `static` `void` `main(String []args)``{``    ``int` `X = ``55``, Y = ``3``;``    ``last_digit(X, Y);``}``}` `// This code is contributed by Rajput-Ji`

## Python3

 `# Python3 Program to find``# the last digit of X in base Y` `# Function to find the last``# digit of X in base Y``def` `last_digit(X, Y) :` `    ``print``(X ``%` `Y);` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:` `    ``X ``=` `55``; Y ``=` `3``;``    ``last_digit(X, Y);` `# This code is contributed``# by AnkitRai01`

## C#

 `// C# Program to find the last digit``// of X in base Y``using` `System;` `class` `GFG``{` `// Function to find the last``// digit of X in base Y``static` `void` `last_digit(``int` `X, ``int` `Y)``{``    ``Console.Write(X % Y);``}` `// Driver code``public` `static` `void` `Main(String []args)``{``    ``int` `X = 55, Y = 3;``    ``last_digit(X, Y);``}``}` `// This code is contributed by Rajput-Ji`

## PHP

 ``

## Javascript

 ``
Output:
`1`

Time Complexity: O(1)

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