2023.5.8

 1 #include <iostream>
 2 using namespace std;
 3 #include <fstream>
 4 #include <iomanip>
 5 void test()
 6 {
 7     int num;
 8     cout << "请输入一个十进制整数：" << endl;
 9     cin >> num;
10     //十进制输出
11     cout << "十进制输出为：" << num << endl;
12     //八进制输出
13     cout << "八进制输出为："<<oct << num << endl;
14     //十六进制输出
15     cout << "十六进制输出为：" << hex << num << endl;
16 }
17 int main()
18 {
19     test();
20     return 0;
21 }

 1 //11-9
 2 #include <iostream>
 3 using namespace std;
 4 #include <fstream>
 5 #include <iomanip>
 6 #include <string>
 7 void test()
 8 {
 9     ofstream ofs;
10     ofs.open("test1.txt", ios::out);
11     ofs << "我说我不再拥有" << endl;
12     ofs << "你说你还爱我" << endl;
13     ofs << "我说我说我开不了口" << endl;
14     ofs.close();
15 }
16 void test01()
17 {
18     string buf;
19     int counter = 0;
20     ifstream ifs("test1.txt",ios::in);
21     ofstream ofs("test2.txt",ios::out);
22     if (!ifs.is_open())
23     {
24         cout << "文件打开失败" << endl;
25         return;
26     }
27     while (getline(ifs, buf))
28     {
29         ofs << ++counter << "." << buf << endl;
30     }
31     ifs.close();
32     ofs.close();
33 }
34 int main()
35 {
36     test();
37     test01();
38     return 0;
39 }

 1 //11-10
 2 #include <iostream>
 3 using namespace std;
 4 #include <fstream>
 5 #include <iomanip>
 6 #include <string>
 7 void test()
 8 {
 9     int num = 0;
10     char c;
11     char a ='我';
12     ifstream ifs;
13     ifs.open("test1.txt", ios::in);
14     if (!ifs.is_open())
15     {
16         cout << "文件打开失败" << endl;
17     }
18 
19     while ((c = ifs.get()) != EOF)
20     {
21 
22         if (a == c)
23         {
24             num++;
25         }
26     }
27     ofstream ofs;
28     ofs.open("test2.txt", ios::out);
29     ofs <<"‘我’的个数为：" << num << endl;
30     ofs.close();
31     ifs.close();
32 }
33 int main()
34 {
35     test();
36     return 0;
37 }