#include 
    
          // std::cout, std::boolalpha, std::noboolalphaint main () {      bool b = true;      std::cout << std::boolalpha;      std::cout << b << std::endl;      std::cout << false << std::endl;      std::cout << std::noboolalpha;      std::cout << b << std::endl;      std::cout << false << std::endl;}
    

输出结果：

truefalse10