60 IO流类库（二）

文件流

ofstream，由ostream派生而来，用于写文件
ifstream，由istream派生而来，用于读文件
fstream，由iostream派生而来，用于读写文件

#include <cassert>#include<iostream>#include <fstream>using namespace std;int main(void){    ofstream fout;    fout.open("test.txt");    if (fout.is_open())    {        cout << "succeed" << endl;    }    else    {        cout << "failed" << endl;    }    if (fout.good())//流状态是否正常    {        cout << "succeed" << endl;    }    else    {        cout << "failed" << endl;    }    if (fout)    {        cout << "succeed" << endl;    }    else    {        cout << "failed" << endl;    }    if (!fout)    {        cout << "failed" << endl;    }    else    {        cout << "succeed" << endl;    }    assert(fout);    fout.close();    return 0;}

文件打开模式