使用C++读写文件

使用(C++库)fstream读写文件

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//awzzz@2002
//入门计划->使用(C++库)fstream读写文件
//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++库)fstream读写文件
//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;
}

Add by : DevEduSiteMaster (2005-4-19:01:26)

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c++文件读写对象，二进制方式和文本方式对比 gaobaolu 发表于 2007-5-21 12:17:00

c++ 文件 读写对象，二进制方式和文本方式对比 //baolu_gao@163.com //测试 文件 读写的二进制形式和文本形式的区别 //该例两种情况结果没有区别，只是文本方式下把10转化成13，10，即16进制0A变为0D OA ＃i nclude <fstream> ＃i nclude <iostream> using namespace std; class Dog { private: int weight; int age; public: Dog(int x=0,int y=0) { weight = x; age = y; } void displayDetails() { cout << weight << "," << age <<endl; } }; int main() { Dog dog1(5,10); //ofstream fout("dogs.dat"); ofstream fout("dogs.dat",ios_base::binary); fout.write((char *) &dog1,sizeof(dog1)); fout.close(); Dog dog2; //ifstream fin("dogs.dat"); ifstream fin("dogs.dat",ios_base::binary); fin.read((char *) &dog2,sizeof dog2); dog2.displayDetails(); fin.close(); system("pause"); return 0; }