C++ setw()函数

// 
#include <iostream>
#include <iomanip>
int main() {
   std::cout << "no setw:" << 42 << '\n'
             << "setw(6):" << std::setw(6) << 42 << '\n'
             << "setw(6), several elements: " << 89 << std::setw(6) << 12 << 34 << '\n';
}