lst-0020-book.cpp
// https://godbolt.org/z/1xzzMdjdM
#include <iostream>
using std::cout; using std::endl;
int main() {
int val = 255;
cout.setf(std::ios_base::hex, std::ios_base::basefield);
cout.setf(std::ios_base::showbase);
cout << val << std::endl; // Output: 0xff
cout.unsetf(std::ios_base::showbase);
cout.setf(std::ios_base::dec, std::ios_base::basefield);
cout << val << std::endl; // Output: 255
}