实验二

task1：

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <time.h>
 4 
 5 #define N 5
 6 #define N1 397
 7 #define N2 476
 8 #define N3 21
 9 
10 int main() {
11     int cnt;
12     int random_major, random_no;
13 
14     srand(time(NULL));      
15 
16     cnt = 0;
17     while(cnt < N) {
18         random_major = rand() % 2;
19 
20         if(random_major) {
21             random_no = rand() % (N2 - N1 + 1) + N1;
22             printf("20248329%04d\n", random_no);
23         }
24         else {
25             random_no = rand() % N3 + 1;
26             printf("20248395%04d\n", random_no);
27         }
28 
29         cnt++;
30     }
31 
32     return 0;
33 }

问题一：

如果random_major生成的数是1，line21是生成一个在N1到N2之前的随机数，并赋值给random_no

问题二：

如果random_major生成的数是0，line25是生成一个在N1和1之间的随机数，并赋值给random_no

问题三：

这个程序的功能是在20248329或20248395后面在一定范围内随机生成四位数。

task2：

 1 #include <stdio.h>
 2 #include <math.h>
 3 
 4 int main() {
 5     double a, b, c;
 6     double delta, p1, p2; 
 7 
 8     while(scanf("%lf%lf%lf", &a, &b, &c) != EOF) {
 9         if(a == 0) {
10             printf("a = 0, invalid input\n");
11             continue;
12         }
13 
14         delta = b*b - 4*a*c;
15         p1 = -b/2/a;
16         p2 = sqrt(fabs(delta))/2/a;
17 
18         if(delta == 0)
19             printf("x1 = x2 = %.2g\n", p1);
20         else if(delta > 0)
21             printf("x1 = %.2g, x2 = %.2g\n", p1+p2, p1-p2);
22         else {
23             printf("x1 = %.2g + %.2gi, ", p1, p2);
24             printf("x2 = %.2g - %.2gi\n", p1, p2);
25         }
26     }
27 
28     return 0;
29 }

task3：

 1 #include<stdio.h>
 2 int main(){
 3     char a;
 4     
 5         while(scanf(" %c",&a)!=EOF){
 6 
 7         if(a == 'r')
 8         printf("stop!\n");
 9         else if(a=='g')
10         printf("go go go\n");
11         else if(a=='y')
12         printf("wait a minute\n");
13         else
14         printf("something must be wrong\n");
15     }
16     return 0;
17 }

task4:

 1 #include<stdio.h>
 2 int main(){
 3     double a;
 4     double max = 0.0;
 5     double min = 20000.0;
 6     double totala = 0.0;
 7     printf("输入今天的开销，知道输入-1终止: ");
 8     while(scanf(" %lf",& a)!=EOF&&a!=-1){
 9         if(a>max)
10         max = a;
11         else if (a<min)
12         min = a;
13     totala=totala+a;}
14     if(max>0&&min<20000&&totala>0){
15     
16         printf("今日最高一笔开销:%.1lf\n",max);
17         printf("今日最低一笔开销:%.1lf\n",min);
18         printf("今日累计消费总额:%.1lf\n",totala);    
19     
20     }else
21     printf("error.\n");
22     
23 
24     return 0;
25 }

task5:

 1 #include<stdio.h>
 2 int main(){
 3     int a,b,c;
 4     while(scanf("%d%d%d",&a, &b, &c)!=EOF){
 5         if(a+b<=c||a+c<=b||b+c<=a){
 6             printf("不能构成三角形\n");
 7         }else{
 8          if(a==b&&b==c){
 9             printf("等边三角形\n");
10         }else if(a==b||b==c||a==c){
11         if(a*a+b*b==c*c||a*a+c*c==b*b||b*b+c*c==a*a){
12             printf("等腰直角三角形\n");
13         }else {
14                 printf("等腰三角形\n");
15             }
16         }else if(a*a+b*b==c*c||a*a+c*c==b*b||b*b+c*c==a*a){
17             printf("直角三角形\n");
18         }else{
19             printf("普通三角形\n"); 
20         }
21     }
22 }
23     
24     return 0;
25     
26 }

task6:

 1 #include<stdio.h>
 2 #include<stdlib.h>
 3 #include<time.h>
 4 
 5 int main(){
 6     srand(time(NULL));
 7     int num = (rand()%30+1);
 8     int a;
 9     int chance = 0;
10     printf("猜猜2024年十一月那一天是你的lucky day");
11     while(chance<3){
12         scanf("%d",&a);
13         if(a==num){
14             printf("You guessed it ringt!\n");
15             return 0;
16         }
17         else if(a>num){
18             printf("你猜的日期晚了\n");
19         }else{
20             printf("你猜的日期早了\n");
21         }
22         chance++;
23     }
24     printf("次数用光啦，偷偷告诉你，11月你的lucky day是%d.\n",num);
25     return 0;
26      
27 }