实验二

任务一

 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     return 0;
32 
33 }

1.生成397-476的随机数

2.生成1-21的随机数

3.以当前的时间作为随机数函数的种子，随机生成五个随机学号

任务二

 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 }

任务三

 1 #include<stdio.h>
 2 int main(){
 3     char sig;
 4     while(scanf("%c",&sig) !=EOF)
 5     {getchar();
 6     
 7     if(sig=='y'){
 8         printf("wait a minute\n");
 9     }
10     else if(sig=='r'){
11         printf("stop!\n");
12     }
13     else if(sig=='g'){
14         printf("go go go\n");
15     }
16     else{
17         printf("something must be wrong...\n");
18     }
19     }
20     return 0;
21 }

任务四

 1 #include<stdio.h>
 2 int main(){
 3     double sum,max,min,data;
 4     sum=0;
 5     max=0;
 6     min=20000;
 7     while(scanf("%lf",&data)!=EOF){
 8         if(data==-1){
 9             break;
10         }
11         sum=sum+data;
12         if(data>max){
13             max=data;
14         }
15         if(data<min){
16             min=data;
17         }
18     }
19     printf("%.1f,%.1f,%.1f",max,min,sum);
20     return 0;
21 }

任务五

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

任务六

 1 #include <stdio.h>
 2 int main(){
 3     int day,i,guess;
 4     srand(time(NULL));
 5     day=rand()%30+1;
 6     printf("猜猜lucky day\n你有三次机会:");
 7     for(i=0;i<3;i++){
 8     scanf("%d",&guess);
 9     if(guess<day){
10         printf("早了\n");
11         printf("再猜:"); 
12     }
13     else if(guess>day){
14         printf("晚了\n");
15         printf("再猜:");
16     }
17     else{
18         printf("猜中了:)");
19         return 0;
20     }
21     }
22     printf("\n次数用光了,luckyday是%d号",day);
23     return 0;
24 }