Please can you tell me where does my program output wrong
answer?

#include <string.h>
#include <assert.h>
#include <fstream.h>
#include <stdio.h>

//ifstream in("hier.in");
#define in cin

double dist(unsigned long x,unsigned long y){
    unsigned long a[32+1],b[32+1];
    int i;
    b[0]=0;
    for(i=1;i<32;i++)
        b[i]=y/(1L<<i)-(x-1)/(1L<<i)-b[i];
    double q=0;
    for(i=2;i<32;i++){
        a[i]=2 * b[i];
        if(y==(1L<<i))
            a[i]--;
        if(x==(1L<<i))
            a[i]--;
               q+=(i-1)*a[i];
    }
    return q;
}

void main(){
    unsigned long x,y,tmp;
    in>>x>>y;
    if(x>y)
        tmp=x,x=y,y=tmp;
        printf("%.0lf\n",dist(x,y));
}