Quick Sort Implementation In Java

Quick Sort Implementation In Java
Sorting Techniques

import java.io.*;
 
class quick
{
 public static int a[];
 public static void main(String args[]) throws IOException
  {
  int a[],n;
   BufferedReader b=new BufferedReader(new InputStreamReader(System.in)); 
   System.out.println(“Enter size of array = “);
   n = Integer.parseInt(b.readLine());
   a = new int[n];
   System.out.println(“Enter values = “);
   for(int i=0;i<n;i++)
     a[i] = Integer.parseInt(b.readLine());
   quick_sort(a,0,n-1);
 for(int i=0;i<n;i++)
System.out.println(“n sorted array is”+a[i]);
  }
 
public static void quick_sort(int x[],int lb, int ub)
{
int j;
if(lb>=ub)
    return;
j=partition(x,lb,ub);
quick_sort(x,lb,j-1);
quick_sort(x,j+1,ub);
  }
public static int partition(int x[],int lb,int ub)
     {
    int a,temp,up,down;
    a=x[lb];
    up=ub;
    down=lb;
     
    while(down<up)
    {
      while(x[down]<=a && down<up)
        down++;
    while(x[up]>a)
    up–;
    if(down<up)
       {
        temp=x[up];
        x[up]=x[down];
        x[down]=temp;
       }
    }
x[lb]=x[up];
x[up]=a;
return up;
}
}