std::setw (an abbreviation of 'set width') is an STL std::iostream manipulator to set the width of the next output.
#include <iomanip> #include <iostream> int main() { const int value = 123; std::cout << "12345678\n" << std::setw(8) << value << '\n' << std::setfill('x') << std::setw(8) << value << '\n'; }
Screen output: