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quicksort partition algorithm

mahmoud2592 (27)
I am trying to code a partition quicksort but the problem here is at the output is in an infinite loop:
the input : 4 3 5 7 2
the expected output : 2 3 4 5 7
but my output is infinite :
2 3 4 5 7
2 3 4 5 7
2 3 4 5 7
.
.
and so on


what is the solu ?

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  #include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
/* Head ends here */
void partition(vector <int>  ar) {
int temp,j=ar.size()-1,i=1,k=0,turn = 0,on_off=1;
do{
    if(ar[j]<ar[k]&&turn==1&&on_off==1)
    {
        temp = ar[j];
        for(int x = j;x>=k;x--)
        {
            if(x!=0&&j!=k)
            {ar[x] = ar[x-1];}
        }
        k++;
        j--;
        ar[0] = temp;
        turn = 0;
        on_off = 0;
        }
        if(ar[j]>ar[k]&&turn==1&&on_off == 1)
        {
            j--;
            turn = 0;
            on_off = 0;
        }
        if(ar[i]<ar[k]&&turn==0&&on_off == 1)
        {
        temp = ar[i];
        for(int x = i;x>=k;x--)
        {
            if(x!=0&&i!=k)
            {ar[x] = ar[x-1];}

        }
        k++;
        i++;
        ar[0] = temp;
        turn = 1;
        on_off = 0;
        }
        if(ar[i]>ar[k]&&turn==0&&on_off == 1)
        {
            i++;
            turn = 1;
            on_off = 0;
        }
        on_off = 1;
         for(int z = 0;z<ar.size();z++)
        {
            cout<<ar[z];
        }
        cout<<endl;
        }while(j+1!=i);

        }

/* Tail starts here */
int main(void) {
   vector <int>  _ar;
   int _ar_size;
cin >> _ar_size;
for(int _ar_i=0; _ar_i<_ar_size; _ar_i++) {
   int _ar_tmp;
   cin >> _ar_tmp;
   _ar.push_back(_ar_tmp);
}

partition(_ar);

   return 0;
}
cire (8284)
Duplicate here: http://www.cplusplus.com/forum/general/109642/
Please direct responses to that thread since it has already garnered some responses.

OP: Please don't crosspost identical posts to different forums.
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