C++学习笔记4--文件操作

标签：style   io   os   ar   使用   for   sp   文件   数据   

#include <iostream>
#include <strstream>
using namespace std;
int main(int argc, char* argv[]) {
    char buf[] = "1002000";
    int i , j;
    istrstream s1(buf);
    s1 >> i;
    istrstream s2(buf, 3); //读进3个字符
    s2 >> j;
    cout << i + j <<endl;
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char* argv[]) {
    ofstream ofile;
    cout << "Create file1" << endl;
    ofile.open("test.txt");
    if(!ofile.fail()) {
        ofile << "lasolmi" << endl;
        ofile.close();
        cout << "Create file2" << endl;
        ofile.open("test2.txt");
        if(!ofile.fail()) {
            ofile << "hello.world!" <<endl;
            ofile.close();
        }
    }
    return 0;
}

#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
int main(int argc, char* argv[]) {
    char buf[128];
    ofstream ofile("test.txt");
    for(int i=0;i<5;i++) {
        memset(buf,0,128);
        cin >> buf;
        ofile << buf;
    }
    ofile.close();
    ifstream ifile("test.txt");
    while(!ifile.eof()) {
        char ch;
        ifile.get(ch);
        if(!ifile.eof()) cout << ch;
    }
    cout << endl;
    ifile.close();
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char* argv[]) {
    fstream file("test.txt",ios::out);
    if(!file.fail()) {
        cout << "start write" << endl;
        file << "lasolmi" << endl;
    }
    else cout << "can not open" <<endl;
    file.close();
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc, char* argv[]) {
    fstream file("test.txt",ios::in);
    if(!file.fail()) {
        while(!file.eof()) {
            char buf[128];
            file.getline(buf,128);
            if(file.tellg() > 0) {
                cout <<buf;
                cout <<endl;
            }
        }
    }
    else cout << "can not open" <<endl;
    file.close();
    return 0;
}

ifstream infile;
ofstream outfile;
infile.open(infilename);
if(!infile) {cout<<"fail open infile"<<endl;}
outfile.open(outfilename);
if(!outfile) {cout<<"fail open outfile"<<endl;}
while(infile.get(c)) outfile << c;
infile.close();
outfile.close();

fstream iofile("test.dat",ios::in|ios::out|ios::binary);
if(iofile) {
    iofile.seekp(0,ios::end); //为了写入移动
    iofile << endl;
    iofile << "我是新加入的";
    iofile.seekg(0); //为了写入移动
    char data[100];
    for(int i=0;!iofile.eof() && i<sizeof(data);i++) iofile.get(data[i]);
    cout << data;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc,char* argv[]) {
    ifstream ifile;
    char cFileSelect[20];
    cout << "input filename:";
    cin >> cFileSelect;
    ifile.open(cFileSelect);
    if(!ifile) {
        cout << cFileSelect << " can not open" << endl;
        return 0;
    }
    ifile.seekg(0,ios::end);
    int maxpos = ifile.tellg();
    int pos;
    cout << "Position:";
    cin >> pos;
    if(pos > maxpos)
        cout << "is over file length" << endl;
    else {
        char ch;
        ifile.seekg(pos);
        ifile.get(ch);
        cout << ch <<endl;
    }
    ifile.close();
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;
int main(int argc,char* argv[]) {
    char file[50];
    cout << "input file name:" << "\n";
    cin >> file;
    if(!remove(file))
        cout << "The file:" << file <<"已删除" << endl;
    else
        cout << "The file:" << file << "删除失败" <<endl;
    return 0;
}

C++学习笔记4--文件操作

标签：style   io   os   ar   使用   for   sp   文件   数据   

原文地址：http://blog.csdn.net/lasolmi/article/details/40583219