5.6.cpp

#include <iostream>
#include <string>
using namespace std;

void print_binary(int x){
    string s = "";
    for(int i=0; i<32 && x!=0; ++i, x >>= 1){
        if(x&1) s = "1" + s;
        else s = "0" + s;
    }
    cout<<s<<endl;
}
int swap_bits(int x){
    return ((x & 0x55555555) << 1) | ((x >> 1) & 0x55555555);
}
// x & 0xAAAAAAAA得出结果是unsigned，所以最高位为1时，右移1位，最高位是0
int swap_bits1(int x){
    return ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >> 1);
}
int main(){
    int x = 0xFFFFFFFF;//-7665543;
    x = x & 0xFFFFFFFF;
    cout<<(x & 0xFFFFFFFF)<<endl;
    print_binary((x | 0xFFFFFFFF) >> 1);
    print_binary(x); 
    print_binary(swap_bits(x));
    print_binary(swap_bits1(x));
    return 0;
}