最简单的方法来创建一个文件在一个函数内写入？
问题描述：
我有一个像这样的函数：
I have a function like so:
void my_func(unordered_map<std::string, std::string> arg){
//Create/open file object on first call and append to file on every call
//Stuff
}
在这个函数里面我想写一个文件。如何实现这一点，而不必在调用者中创建文件对象，并将其作为参数传递？每次调用函数时，我想将最新的写入附加到文件末尾。
and inside this function I wish to write to a file. How can I achieve this without having to create the file object in the caller and pass it in as a parameter? Each time the function is called I would like to append the latest write to the end of the file.
答
void my_func(unordered_map<std::string, std::string> arg){
static std::ofstream out("output.txt");
// out is opened for writing the first time.
// it is available for use the next time the function gets called.
// It gets closed when the program exits.
}