quicksort.java

import java.util.Scanner;
public class quicksort {
String ar[];int l;
public static void main(String args[]) {
Scanner in=new Scanner(System.in);
quicksort s=new quicksort();

int size,i;
String name[]=new String[20];
 System.out.println("Enter the number of elements");
size=in.nextInt();
for(i=0;i<size;i++) {
System.out.println("Enter name");
name[i]=in.next();
}
s.sort(name,size);


System.out.println("Sorted Array");
for (i=0;i<size;i++) {
         System.out.print(name[i]);
         System.out.print(" ");
}
}

void sort(String array[],int size) {
       if (array == null || array.length == 0) {
           return ;
       }
       else{
        this.ar = array;
        this.l = size;
       quick(0, l - 1);
       }        
   }

void quick(int f,int l) {
int i=f,j=l;

String pivot=this.ar[f+(l-f)/2];
while (i <= j) {
        while (this.ar[i].compareToIgnoreCase(pivot) <0){
            i++;
        }

        while (this.ar[j].compareToIgnoreCase(pivot) > 0) {
            j--;
        }

        if (i <= j) {
            exchange(i, j);
            i++;
            j--;
        }
    }
    if (f < j) {
        quick(f, j);
    }
    if (i < l) {
        quick(i, l);
    }
}


void exchange(int i,int j) {
String temp = this.ar[i];
    this.ar[i] = this.ar[j];
    this.ar[j] = temp;
}
}