c program to find Quark pair

#include<stdio.h>
int bin(int );

int bin(int n) //this fn retuns total no. of 1 in n * n
{
   int i=0,j,n1,t,arr[100],count=0;
   t=n;
   while(n!=0)
     {
        n1=n%2;
        n=n/2;
        arr[i++]=n1;

     }

    for(j=i-1;j>=0;j--)
      {

        if(arr[j]==1)
        count=count+1;
      }

      return count*t;
}

int main()
{
    int n,i,j,y,z;
    printf("Enter value of n:");
    scanf("%d",&n);

    for(i=0;i<=n;i++)
    {
        y=bin(i);

        for(j=i+1;j<=n;j++)
        {
            z=bin(j);

            if(y==z)
            {
              printf("Quarks pair: %d %d\n" ,i,j);
            }

        }

    }

}