C style
FILE * fileptr
filename="C:\\file.txt"
fopen
fclose
fprintf
C++ style
//指向std::ostream的指针
#include <iostream>
#include <fstream>
int main() {
std::ostream* output = &std::cout; // 默认指向控制台
// 输出到控制台
*output << "Hello, Console!" << std::endl;
// 切换到文件
std::ofstream file("output.txt");
output = &file;
*output << "Hello, File!" << std::endl;
// 恢复控制台输出
output = &std::cout;
*output << "Back to Console!" << std::endl;
file.close();
return 0;
}