std::basic_ofstream

#include <iostream>
#include <fstream>
#include <string>
 
int main() {
	std::string filename = "Test.b";
	{
		std::ofstream ostrm(filename, std::ios::binary);
		double d = 3.14;
		ostrm.write(reinterpret_cast<char*>(&d), sizeof d); // 二进制输出
		ostrm << 123 << "abc" << '\n';                      // 文本输出
	}
 
	// 回读
	std::ifstream istrm(filename, std::ios::binary);
	double d;
	istrm.read(reinterpret_cast<char*>(&d), sizeof d);
	int n;
	std::string s;
	istrm >> n >> s;
	std::cout << " read back: " << d << " " << n << " " << s << '\n';
}