Using Divide and Conquer Strategies design a class for Concurrent Quick Sort using C++

PROGRAM

file name a2.cpp

#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
using namespace std;

struct array
{
 int *arr;
 int first;
 int last;
};
int n;

void* quick(void *in)
{
array* a=(array*)in;
int i,j;
pthread_t id=pthread_self();
if(a->first < a->last)
{
int temp=0;
int i=a->first;
int j=a->last;
int pivot=a->arr[a->first];
while(i<j)
{
 while(a->arr[i] <=pivot && i<j)
 i++;
 while(a->arr[j] > pivot && i<=j)
 j--;
 if(i<=j)
 {
 temp=a->arr[i];
 a->arr[i]=a->arr[j];
 a->arr[j]=temp;
 }
}
 temp=a->arr[j];
 a->arr[j]=a->arr[a->first];
 a->arr[a->first]=temp;

pthread_t threads[2];
cout<<"Thread ID: "<<id<<" for pivot: "<<pivot<<endl;
array a1,a2;
a1.arr=new int[n];
a2.arr=new int[n];
a1.arr=a->arr;
a2.arr=a->arr;
a1.first=a->first;
a1.last=j-1;
a2.first=j+1;
a2.last=a->last;
pthread_create(&threads[0],NULL,&quick,(void *)&a1);
pthread_create(&threads[1],NULL,&quick,(void *)&a2);
pthread_join(threads[0],NULL);
pthread_join(threads[1],NULL);
}
}

int main()
{
array a1;
int n,i;
cout<<"Enter size of array: ";
cin>>n;
a1.arr=new int[n];
a1.first=0;
a1.last=n-1;
cout<<"Enter elements:"<<endl;
for(i=0;i<n;i++)
 cin>>a1.arr[i];
quick(&a1);
cout<<"Sorted array is:"<<endl;
for(i=0;i<n;i++)
 cout<<a1.arr[i]<<" ";
cout<<endl;
return 0;
}


OUTPUT

[amodi@localhost ~]$ g++ a2.cpp -pthread
[amodi@localhost ~]$ ./a.out
Enter size of array: 4
Enter elements:
23
42
73
25
Thread ID: 140425762199424 for pivot: 23
Thread ID: 140425753798400 for pivot: 42
Sorted array is:
23 25 42 73