C++之重定向

#include "stdafx.h"
#include <iostream>
#include <fstream>
int main(int argc, char* argv[])
{
    using namespace std;
    cout << "Hello, Let‘s begin a test of cout to file." << endl;
    // 保存cout流缓冲区指针
     streambuf* coutBuf = cout.rdbuf();
    ofstream of("out.txt");
    // 获取文件out.txt流缓冲区指针
     streambuf* fileBuf = of.rdbuf();

    // 设置cout流缓冲区指针为out.txt的流缓冲区指针
     cout.rdbuf(fileBuf);
    cout << "Name " << "Chen"        << endl;
    cout << "Sex  " << "Female"      << endl;
    cout << "E-mail"<< "[email protected]" << endl;
    of.flush();
    of.close();
    // 恢复cout原来的流缓冲区指针
     cout.rdbuf(coutBuf);
    cout << "Write Personal Information over..." << endl;
    system("PAUSE");
    return 0;
}

C++是通过rdbuf函数来进行流重定向的，例如：

#include <iostream>
#include <fstream>

using std::cout;
using std::streambuf;
using std::rdbuf;
using std::ofstream;

int main( void )
{
    ofstream fout( "out.txt" );
    streambuf * OldBuf = cout.rdbuf( fout.rdbuf( ) ); //保存cout的流缓冲类指针并用fout的流缓冲类指针代替
     cout << "example";  //cout的内容被写入文件out.txt中
     cout.rdbuf( OldBuf );  //恢复cout的流缓冲类指针
     cout << "reload";  //恢复输出到终端
     return 0;
}

C++之重定向