C++文件读写demo

 1 #include<iostream>
 2 #include<fstream>
 3 using namespace std;
 4 
 5 void test()
 6 {
 7     //ofstream ofs("test.txt",ios::out);    //创建流对象，并创建文件和打开方式
 8     ofstream ofs;    //创建流对象
 9     ofs.open("test.txt", ios::out);    //创建文件和打开方式
10     ofs << "姓名：码子" << endl;
11     ofs << "年龄：18" << endl;
12     ofs.close();    //关闭文件
13 }
14 
15 int main()
16 {
17     test();
18 
19     return 0;
20 }

 1 #include<iostream>
 2 #include<fstream>
 3 #include<string>
 4 using namespace std;
 5 
 6 void test()
 7 {
 8     ifstream ifs;
 9     ifs.open("test.txt", ios::in);
10     //判断是否打开文件
11     if (!ifs.is_open())
12     {
13         cout << "打开文件失败" << endl;
14     }
15     //第一种读取方式
16     /*char buf[1024] = "";
17     while (ifs>>buf)
18     {
19         cout << buf << endl;
20     }*/
21 
22     //第二种读取方式
23     /*char buf[1024] = "";
24     while (ifs.getline(buf,sizeof(buf)))
25     {
26         cout << buf << endl;
27     }*/
28 
29     //第三种读取方式
30     string buf = "";
31     while (getline(ifs, buf))
32     {
33         cout << buf << endl;
34     }
35 
36     //第四种读取方式，不推荐
37  /*   char c;
38     while ((c = ifs.get()) != EOF)
39     {
40         cout << c;
41     }*/
42 
43     ifs.close();
44 }
45 
46 int main()
47 {
48     test();
49 
50     return 0;
51 }

 1 #include<iostream>
 2 #include<fstream>
 3 #include<string>
 4 using namespace std;
 5 
 6 class Cat
 7 {
 8 public:
 9     Cat(const char name[] = "", int age = 0,const char color[]="")
10     {
11         strcpy_s(m_Name, name);
12         strcpy_s(m_Color,color);
13         m_Age = age;
14     }
15     char m_Name[32];
16     char m_Color[32];
17     int m_Age;
18 };
19 
20 void test1()
21 {
22     Cat c("老黄",2,"Yellow");
23     ofstream ofs("Cat.txt", ios::out | ios::binary);    //创建流对象，并设置打开文件方式
24     ofs.write((const char*)&c, sizeof(c));    //写入文件
25     ofs.close();    //关闭文件
26 }
27 
28 int main()
29 {
30     test1();
31     return 0;
32 }

 1 #include<iostream>
 2 #include<fstream>
 3 #include<string>
 4 using namespace std;
 5 
 6 class Cat
 7 {
 8 public:
 9     Cat(const char name[] = "", int age = 0,const char color[]="")
10     {
11         strcpy_s(m_Name, name);
12         strcpy_s(m_Color,color);
13         m_Age = age;
14     }
15     char m_Name[32];
16     char m_Color[32];
17     int m_Age;
18 };
19 
20 
21 void test2()
22 {
23     Cat c;
24     ifstream ifs("Cat.txt", ios::in | ios::binary);    //创建流对象，并设置打开文件方式
25     //验证是否成功打开文件
26     if (!ifs.is_open())
27     {
28         cout << "文件打开失败" << endl;
29     }
30     ifs.read((char*)&c, sizeof(c));    //读出文件
31     cout << "名字: " << c.m_Name << endl;
32     cout << "颜色: " << c.m_Color << endl;
33     cout << "年龄: " << c.m_Age << endl;
34     ifs.close();        //关闭文件
35 }
36 
37 int main()
38 {
39     test2();
40     return 0;
41 }