Radix_Sort.cs

// C# implementation of Radix Sort
using System;

class GFG {
	public static int getMax(int[] arr, int n)
	{
		int mx = arr[0];
		for (int i = 1; i < n; i++)
			if (arr[i] > mx)
				mx = arr[i];
		return mx;
	}

	// A function to do counting sort of arr[] according to
	// the digit represented by exp.
	public static void countSort(int[] arr, int n, int exp)
	{
		int[] output = new int[n]; // output array
		int i;
		int[] count = new int[10];

		// initializing all elements of count to 0
		for (i = 0; i < 10; i++)
			count[i] = 0;

		// Store count of occurrences in count[]
		for (i = 0; i < n; i++)
			count[(arr[i] / exp) % 10]++;

		// Change count[i] so that count[i] now contains
		// actual
		// position of this digit in output[]
		for (i = 1; i < 10; i++)
			count[i] += count[i - 1];

		// Build the output array
		for (i = n - 1; i >= 0; i--) {
			output[count[(arr[i] / exp) % 10] - 1] = arr[i];
			count[(arr[i] / exp) % 10]--;
		}

		// Copy the output array to arr[], so that arr[] now
		// contains sorted numbers according to current
		// digit
		for (i = 0; i < n; i++)
			arr[i] = output[i];
	}

	// The main function to that sorts arr[] of size n using
	// Radix Sort
	public static void radixsort(int[] arr, int n)
	{
		// Find the maximum number to know number of digits
		int m = getMax(arr, n);

		// Do counting sort for every digit. Note that
		// instead of passing digit number, exp is passed.
		// exp is 10^i where i is current digit number
		for (int exp = 1; m / exp > 0; exp *= 10)
			countSort(arr, n, exp);
	}

	// A utility function to print an array
	public static void print(int[] arr, int n)
	{
		for (int i = 0; i < n; i++)
			Console.Write(arr[i] + " ");
	}

	// Driver Code
	public static void Main()
	{
		int[] arr = { 170, 45, 75, 90, 802, 24, 2, 66 };
		int n = arr.Length;

		// Function Call
		radixsort(arr, n);
		print(arr, n);
	}

	// This code is contributed by DrRoot_
}