Cpp_note_1

C++笔记汇总1 文件操作

#include <bits/stdc++.h>
using namespace std;
// 1.文本文件
// 写文件
void test01() {
    ofstream ofs;
    ofs.open(
        "D:\\coding_file\\study\\C++_file\\Other_file\\note_file\\Other\\File_"
        "Operation\\in.txt",
        ios::out);
    ofs << "hello world" << endl;
    ofs << "hello C++" << endl;
    ofs.close();
}
// 读文件
void test02() {
    ifstream ifs;
    ifs.open(
        "D:\\coding_file\\study\\C++_file\\Other_file\\note_file\\Other\\File_"
        "Operation\\in.txt",
        ios::in);
    if (!ifs.is_open()) {
        cout << "fail" << endl;
        return;
    } else {
        //四种读数据的方法
        //方法1.
        char buf[1024] = {0};
        while (ifs >> buf) {
            cout << buf << endl;
        }
        // 方法2
        /*         char buf[1024] = {0};
                while (ifs.getline(buf, sizeof(buf))) {
                    cout << buf << endl;
                } */
        //方法3
        /*         string buf;
                while (getline(ifs, buf)) {
                    cout << buf << endl;
                } */
        // 方法4
        /*         char c;
                while ((c = ifs.get()) != EOF) {
                    cout << c;
                } */
        ifs.close();
    }
}
//二进制文件
// 写文件
class Person {
   public:
    char name[64];
    int age;
};
void test03() {
    ofstream ofs(
        "D:\\coding_file\\study\\C++_file\\Other_file\\note_file\\Other\\File_"
        "Operation\\b_in.txt",
        ios::out | ios::binary);
    Person p = {"张三", 18};
    ofs.write((const char*)&p, sizeof(p));
    ofs.close();
}
//读文件
void test04() {
    ifstream ifs(
        "D:\\coding_file\\study\\C++_file\\Other_file\\note_file\\Other\\File_"
        "Operation\\b_in.txt",
        ios::in | ios::binary);
    if (!ifs.is_open()) {
        cout << "fail" << endl;
        return;
    } else {
        Person p;
        ifs.read((char*)&p, sizeof(p));
        cout << p.name << endl;
        cout << p.age << endl;
    }
    ifs.close();
}
int main() {
    ios::sync_with_stdio(false);
    cout.tie(NULL);
    test01();
    test02();
    test03();
    test04();
    return 0;
}