Java Program to perform Radix Sort

Radix Sort is a type of bucket sort. This type of sort is based on radix i.e. 10 for decimal numbers and 26 for alphabets. This technique is very useful in sorting words alphabetically. Arrays are sorted in a total of "d" passes where "d" is the number of digits of highest number..
For decimal numbers : In first pass array is sorted according to units digit , then in next pass sorted according to tens digit and so on.This process goes on till all the digits of highest numbers are traversed.
For words : In first pass array is sorted according to first letter , and in second pass second character is considered and so on.
Here is the code for you -->

import java.io.*;
public class Radix_Sort {

    public void sort(int a[],int rad,int max){
        int tmp[][]=new int[a.length][10];

        for(int i=0;i<max;i++){

            int c=0;
            for (int j=0;j<a.length;j++)
                for(int k=0;k<rad;k++)
                    tmp[j][k]=0;

            for(int k=0;k<a.length;k++){
                int d=(int)((a[k]/Math.pow(10,i))%10);
                tmp[k][d]=a[k];
            }

            for (int j=0;j<rad;j++)
                for(int k=0;k<a.length;k++)
                    if(tmp[k][j]!=0)
                        a[c++]=tmp[k][j];
        }

        disp(a);
    }

    public void input()throws Exception{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter array size : ");
        int n=Integer.parseInt(br.readLine());
        int a[]=new int[n];
        System.out.println("Enter elements in array ------->");
        int max=0;
        for (int i = 0; i<n; i++) {
            System.out.print("Enter number : ");
            a[i]=Integer.parseInt(br.readLine());
            if(a[i]>max)
                max=a[i];
        }
        sort(a,10,digit_count(max));
     }

    int digit_count(int n){
        int d=0;
        while (n!=0) {
            d++;
            n/=10;
        }
        return d;
    }

    public void disp(int a[]){
        System.out.println("\nArray after sorting -------->");
        for (int i = 0; i<a.length; i++)
            System.out.print(a[i]+"  ");
    }

    public static void main(String[] args) throws Exception{
        new Radix_Sort().input();
    }
}

You can also download the source from below links :
DOWNLOAD source JAVA file from MediaFire
DOWNLOAD the JAVA file from 4shared