c – 创建一个打印函数,该函数将ostream作为参数并写入该流

你一定错过了什么,因为ostream很重要.顺便说一句,std :: cout是std :: ostream类型的变量.用法或多或少是这样的

#include <iostream> //defines "std::ostream",and creates "std::ofstream std::cout"
#include <fstream> //defines "std::ofstream" (a type of std::ostream)
std::ostream& dostuffWithStream(std::ostream &out) { //defines a function
    out << "apples!";
    return out;
}
int main() {
    std::cout << "starTing!\n"; 
    dostuffWithStream(std::cout); //uses the function

    std::ofstream fiLeout("C:/myfile.txt"); //creates a "std::ofstream"
    dostuffWithStream(fiLeout); //uses the function

    return 0;
}