入門計劃->使用(C++庫)fstream讀寫文件

//入門計劃->使用(C++庫)fstream讀寫文件
//APO->using fstream.
//accidence project of using fstream.(c++ iostream library)

/*
Reference: http://www.cplusplus.com/ref/iostream/fstream/

Description

fstream class provides a stream interface to read and write data from/to files.

The class mantains internally (privately) a pointer to a filebuf object in charge
of the interaction with the file. This pointer can be obtained/modified by calling
member rdbuf.

The file to be processed can be specified as a parameter for the constructor or by
calling member open.

After a file is processed it can be closed by calling member close. In this case
the file stream may be used to open another file.

Member is_open can be used to determine wether the stream is currently operating
on a file or not.

Please refer to parent classes for more details on information mantained by an
fstream object.
*/

//使用(C++庫)fstream讀寫文件
//simple example

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

#ifdef WIN32
#define TEST_FILE   "c://tmp//test.txt"
#else
#define TEST_FILE   "/tmp/test.txt"
#endif

void test()
{
    {
        //fstream sfs;
        //sfs.open(TEST_FILE, ios_base::out);
        fstream sfs(TEST_FILE, ios_base::out);
       
        char buf[] = "1234567890";
        sfs.write(buf, sizeof(buf));

        sfs.close();
    }

    {
        int len;
        char* buf;

        //fstream sfs;
        //sfs.open(TEST_FILE);
        fstream sfs(TEST_FILE);
       
        sfs.seekg (0, ios::end);
        len = sfs.tellg();
        sfs.seekg (0, ios::beg);

        buf = new char[len];
        sfs.read(buf, len);
        cout << buf << endl;
        delete []buf;

        sfs.close();
    }
}

int main(int argc, char* argv[])
{  
    test();
    return 0;
}