c++ program to count number of bits in binary representation of an integer

#include <iostream>

using namespace std;

    //Write your countBits function here
bool countBits(int n)
{if(n==1)
         return true;
    
    return false;
}
int main() {
    int n;
    cin >> n;
   int sum=0;
    while(n!=0)
    {
        int d=n%2;  
         n=n/2;
         bool t=countBits(d);
    if(t==true)
        sum++;}
   cout<<sum;
    return 0;
}