#include<fstream>

// 写文件

std::ofstream write_file;

// 文件不存在会创建新的。

write_file.open("iof_file.txt");

write_file << "hello world" << endl << "save the world";

write_file.close();

#include<fstream>

// 读文件

string read_val;

std::ifstream read_file;

read_file.open("iof_file.txt");

if (!read_file.is_open())return;

while (read_file.good())

{

    // 会忽略空格

    /*read_file >> read_val;

    cout << read_val;*/

    // 这样就不会

    getline(read_file, read_val);

    cout << read_val << endl;

}

if (read_file.eof()) {

	cout << "read over" << endl;

}

else if (read_file.fail()) {

	cout << "read fail!!!" << endl;

}

read_file.close();