实验2

 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%d04\n",number);
13     }
14     return 0;
15 }

一：在1—500之间取一个数字

二：随机生成一串数字

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <stdio.h>
 3 #include <stdlib.h>
 4 #include <time.h>
 5 
 6 int main()
 7 {
 8     int number;
 9     int n;
10     int i;
11 
12     srand(time(0));
13     number = rand() % 30 + 1;
14     printf("猜猜那一天会是你的Lucky day\n");
15     printf("开始喽，你有三次机会，猜吧（1~30）：\n");
16     for (i = 1; i <= 3; i++)
17     {
18         scanf_s("%d", &n);
19         getchar();
20 
21         if (n == number)
22         {
23             printf("你猜中了");
24             break;
25         }
26         if (n < number)
27         {
28             printf("你猜的日期早了，Lucky day还没到呢\n");
29         }
30         if (n > number)
31         {
32             printf("你猜的日期晚了，Lucky day已经过啦\n");
33         }
34         if (i == 3) {
35             printf("次数用光啦,偷偷告诉你：11月，你的Lucky day是%3d号\n", number);
36             break;
37         }
38         if (i <= 2) {
39             printf("再猜:\n");
40         }
41     }
42 
43 
44     return 0;
45 }

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include<stdio.h>
 3 int main()
 4 {
 5     char x;
 6 
 7     while (scanf_s(" %c", &x) != EOF)
 8     {
 9         switch (x)
10         {
11         case 'r':printf("stop\n"); break;
12         case 'g':printf("gogogo\n"); break;
13         case 'y':printf("wait a moment\n"); break;
14         default:printf("something must be wrong \n");
15 
16         }
17 
18     }
19     return 0;
20 }

 1 #include<stdio.h>
 2 int main() 
 3 {
 4     int i,j;
 5     for(i=1;i<=9;i++)
 6     {
 7         for(j=1;j<=i;j++)
 8         {
 9         printf("%d*%d=%d",i,j,i*j);
10         printf(" ");
11     }
12     printf("\n");
13 }
14     return 0;
15 }

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #include<math.h>
 4 #define _CRT_SECURE_NO_WARNINGS
 5 int main()
 6 {
 7     int i, n, a, t;
 8 
 9     while (scanf_s("%d %d", &n, &a) != EOF)
10     {
11         double s = 0, t = 0;
12         for (i = 1; i <= n; i++)
13         {
14             t = 10 * t + a;
15             s = s + (double)i / t;
16 
17         }
18         printf("n=%d,a=%d,s=%f\n", n, a, s);
19 
20     }
21     return 0;
22 }

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include<stdio.h>
 3 int main()
 4 {
 5     int i, m, n;
 6     scanf("%d", &n);
 7     for (i = 1; i <= n; i++) {
 8         for (m = 1; m < i; m++) {
 9             printf(" \t");
10         }
11         for (m = 1; m <= 2 * (n - i) + 1; m++) {
12             printf(" O \t");
13         }
14         printf("\n");
15         for (m = 1; m < i; m++) {
16             printf(" \t");
17         }
18         for (m = 1; m <= 2 * (n - i) + 1; m++) {
19             printf("<H>\t");
20         }
21         printf("\n");
22         for (m = 1; m < i; m++) {
23             printf(" \t");
24         }
25         for (m = 1; m <= 2 * (n - i) + 1; m++) {
26             printf("I I\t");
27         }
28         printf("\n");
29         printf("\n");
30     }
31     return 0;
32 }