四则运算

1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <time.h>
4 #include <math.h>
5
6 int main()
7 {
8 int i=0;
9 int n=0;
10 int x=0;
11 int type;
12 char flag;
13 int left, right;
14 float result;
15 printf("请输入要出的题目数量 ");
16 scanf("%d",&n);
17 srand(unsigned(time(NULL)));
18 while(x<n)
19 {
20 type = rand() % 4;
21 left = rand() % 100;
22 right = rand() % 100;
23 switch(type)
24 {
25 case 0:
26 printf("%d + %d = ? ", left, right);
27 break;
28 case 1:
29 printf("%d - %d = ? ", left, right);
30 break;
31 case 2:
32 printf("%d * %d = ? ", left, right);
33 break;
34 case 3:
35 printf("%d / %d = ? ", left, right);
36 break;
37 }
38
39 i++;
40 while(i>=n)
41 {
42 printf("一共 %d 题 ",i);
43 printf("继续?[Y/N] ");
44 fflush(stdin);
45 scanf("%c",&flag);
46 if(flag=='Y'||flag=='y')
47 {
48 printf("请输入要出的题目数量 ");
49 scanf("%d",&n);
50 i=0;
51 break;
52 }
53 printf("谢谢使用！ ");
54 fflush(stdin);
55 getchar();
56 return 0;
57 }
58 }
59 }