1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <time.h>
 4 #define N 5
 5 int main()
 6 {
 7     int number;
 8     int i;
 9     srand(time(0));
10     for (i = 0; i < N; ++i) {
11         number = rand() % 500 + 1;
12         printf("20228329%04d\n", number);
13     }
14     return 0;
15 }
16 
17 
18 
19 
20 //问题1：从1~500中随机产生1个数
21 
22 //问题2：随机点5个学号在202283290001-202283290500的学生

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <time.h>
 4 int main()
 5 {
 6     srand(time(0));
 7     int day, a;
 8     day= rand() % 30+ 1;
 9     printf("猜猜2022年11月哪一天会是你的lucky day\n开始喽，你有三次机会，猜吧（1~30）：\n");
10     for (int i = 0; i < 3; i++)
11     {
12         scanf_s("%d", &a);
13         if (a == day)
14         {
15             printf("哇，猜中了\n");
16             break;
17         }
18         else if (a > day)
19         {
20             printf("你的日期晚了，你的lucky day 已经过了\n");
21             continue;
22         }
23         else (a < day);
24         {
25             printf("你的日期早了，你的lucky day 还没到呢\n");
26             continue;
27         }
28         
29     }
30     if  (a != day)
31     {
32         printf("次数用完啦下，偷偷告诉你:11月你的licky day 是%d号", day);
33     }
34 
35 
36 }

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 int main()
 4 {
 5     char a;
 6     
 7     for (;;)
 8     {
 9         scanf_s("%c", &a);
10         getchar();
11 
12         switch (a)
13         {
14         case 'r':
15             printf("stop!\n");
16             break;
17         case 'y':
18             printf("wait a minute\n");
19             break;
20         case 'g':
21             printf("go go go\n");
22             break;
23         default:
24             printf("something must be wrong...\n");
25         }
26     }
27 }

 1 #include<stdio.h>
 2 #include<math.h>
 3 int main()
 4 {
 5     for (;;)
 6     {
 7         double s = 0.0;
 8         int a, n,t;
 9         
10 
11         scanf_s("%d%d", &n, &a);
12         printf("n=%d  a=%d\n", n, a);
13         t = a;
14         for (int i = 1; i <= n; i++)
15         {
16             
17             s =s+ i *1.0/ t;
18             t = 10 * t + a;
19         }
20         printf("s=%lf", s);
21 
22     }
23 
24 
25 }

 1 #include<stdio.h>
 2 int main()
 3 {
 4     int s;
 5 
 6 
 7     for (int i = 1; i <= 9; i++)
 8     {
 9         for (int j = 1; j <= i; j++)
10         {
11             s = i * j;
12 
13             printf("%d*%d=%d\t",i,j ,s);
14 
15         }
16         printf("\n");
17     }
18 
19 
20 
21 
22 }

 1 //第i行有2n-2i+1个小人
 2 //第i行有i—1个\t
 3 
 4 #include<stdio.h>
 5 void space(int n)
 6 {
 7     for (int j = 1; j <= n; j++)
 8     {
 9         printf("\t");
10     }
11 }
12 void people(int q)
13 {
14     for (int m = 1; m <= q; m++)
15     {
16 
17         printf(" O \n");
18         printf("<H>\n");
19         printf("I I\n");
20     }
21 }
22 void head(int q)
23 {
24     for (int m = 1; m <= q; m++)
25     {
26     
27     printf(" O \t");
28     
29     }
30 }
31 void body(int q)
32 {
33     for (int m = 1; m <= q; m++)
34     {
35 
36         
37         printf("<H>\t");
38         
39     }
40 }
41 void leg(int q)
42 {
43     for (int m = 1; m <= q; m++)
44     {
45 
46         
47         printf("I I\t");
48     }
49 }
50 int main()
51 {
52     int s;
53     printf("请输入共多少行：");
54     int t;
55     int n;
56     scanf_s("%d", &n);
57     for (int i = 1; i <= n; i++)
58     {
59         s = i - 1;
60         t = 2 * n - 2 * i + 1;
61         space(s);
62         head(t);
63         
64         printf("\n");
65         space(s);
66         body(t);
67         printf("\n");
68         space(s);
69         leg(t);
70         
71 
72 
73         printf("\n");
74     }
75 
76 }