c++ - Printing std::bitset in C++11 -

consider following code written in c++11:

#include <iostream> #include <bitset> #include <cstdint>  int main() {      std::uint64_t = 0000000000000000000000000000000000000000000000001111111100000000;     std::bitset<64> b(a);      std::cout << b << std::endl;      return 0; } 

the output of code :

0000000000000000001001001001001001001001000000000000000000000000 

why output not correspond a value?

if want write binary number need use 0b prefix.

std::uint64_t = 0b0000000000000000000000000000000000000000000000001111111100000000; std::bitset<64> b(a); 

your example fixed , working live