小杨用文件重定向实现在 log.txt 文件中输出日志，则下面横线上应填写（ ）。

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main() {
    ofstream log_file("log.txt");

    streambuf* original_cout = cout.rdbuf();
    cout.rdbuf(log_file.rdbuf());

    _________________________________ // 在此处填入代码

    cout.rdbuf(original_cout); // 恢复原始的标准输出缓冲区
    return 0;
}

{{ select(1) }}

• cout << "This output will go to the log file." << endl;
• log_file << "This output will go to the log file." << endl;
• cout >> "This output will go to the log file." >> endl;
• log_file >> "This output will go to the log file." >> endl;