reverse binary simply

reverse binary simplified

#include <iostream>
#include <bitset>

//reverse binary of a number
unsigned int flipping2(unsigned int a)
{
    //input: 0000010110
    //output:0000001101
    unsigned int f = 0x0;
    unsigned int size = sizeof(a) * 8;
    unsigned int l = 0;
    short lastbit = 0;
    while(size--){
        l = ((unsigned int)(1 & a) )<< size;
        if(1&a){
            lastbit = size;
        }
        a >>= 1;
        f |= l;
    }
    f >>= lastbit;
    return f;
}   

// 101

int main(void){
    unsigned int n;
    std::cin >> n;
    unsigned int f = flipping2(n);
    std::cout << std::bitset<32>(f);
    
}