decimal to binary string.

bitset_sstream.cpp

#include <iostream>
#include <string>
#include <bitset>  // static_cast<std::bitset<8>>
#include <sstream>  // std::stringstream
using namespace std;

int main() {
    int num = 55;
    stringstream ss;
    ss << std::bitset<8>(num);
    string s = ss.str();
    cout << s << "\n";
    
    return 0;
}