实验2

 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 #define N 5
 #define N1 397
 #define N2 476
 #define N3 21
 int main() {
 int cnt;
 int random_major, random_no;
 srand(time(NULL));      
cnt = 0;
 while(cnt < N) {
 random_major = rand() % 2;
 
if(random_major) {
 random_no = rand() % (N2 - N1 + 1) + N1;
 printf("20248329%04d\n", random_no);
 }
     else {
     random_no = rand() % N3 + 1;
     printf("20248395%04d\n", random_no);
     }
     cnt++;
  }
  return 0;
 }

1.随机选取379到476中的数

2.随机选取1到21中的数

3.随机生成学号

#include <stdio.h>
 #include <math.h>
 int main() {
    double a, b, c;
    double delta, p1, p2; 
    while(scanf("%lf%lf%lf", &a, &b, &c) != EOF) {
        if(a == 0) {
            printf("a = 0, invalid input\n");
            continue;
        }
        delta = b*b - 4*a*c;
        p1 = -b/2/a;
        p2 = sqrt(fabs(delta))/2/a;
        if(delta == 0)
            printf("x1 = x2 = %.2g\n", p1);
        else if(delta > 0)
            printf("x1 = %.2g, x2 = %.2g\n", p1+p2, p1-p2);
        else {
            printf("x1 = %.2g + %.2gi, ", p1, p2);
            printf("x2 = %.2g - %.2gi\n", p1, p2);
        }
    }
    return 0;
 }

#include<stdio.h>
int main(){
    char color;
    while(scanf("%c",&color)!=EOF){
        getchar();
        if(color=='r')
         printf("stop\n");
        else if(color=='g')
         printf("go go go\n");
        else if(color=='y')
         printf("wait a minute\n");
        else
         printf("something must be wrong...\n");
    }
    return 0;
}

include <stdio.h>
  
  int main(){
      double money,max = 0,min = 20000,total=0;
      
      printf("请输入今日开销，直到输入-1终止：\n");
      
      while(1){
          scanf("%lf",&money);
         
         if(money == -1){
             break;
         }
         if(money < min){
             min = money;
         }
         if(money > max){
             max = money;
         }
         total += money;
     }
     
     printf("今日累计消费总额：%.1f\n",total);
     printf("今日最高一笔开销：%.1f\n",max);
     printf("今日最低一笔开销：%.1f\n",min);
     
     return 0;
 }

#include <stdio.h>
  
  int main(){
      int a,b,c;
      
      while(scanf("%d%d%d",&a,&b,&c) !=EOF){
          if(a+b<=c||b+c<=a||a+c<=b)
           printf("不能构成三角形\n");
          else if(a==b&&b==c)
          printf("等边三角形\n");
         else if(a==b||b==c||a==c)
          printf("等腰三角形\n");
         else if(a*a==b*b+c*c||b*b==a*a+c*c||c*c==a*a+b*b)
          printf("直角三角形\n");
         else
          printf("普通三角形\n");
     }
     
     return 0;
 }

 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 
 int main(){
     int luckyday,x,y=3;
     
     printf("猜猜2024年11月哪一天会是你的lucky day\n"); 
     
     srand(time(NULL));
     luckyday = rand() % 30 + 1;
     
     printf("开始喽，你有三次机会，猜吧（1~30）：");
     
     while(y>0){
         scanf("%d",&x);
         
         if(x==luckyday){
             printf("哇，猜中了:)");
             return 0;
         }
         else if(x>luckyday){
             printf("你猜的日期晚了，你的lucky day在前面哦\n");
         }
         else{
             printf("你猜的日期早了，你的lucky day还没到呢\n");
         }
         printf("再猜（1~30）：");
         y--;
     }
     printf("次数用光啦。偷偷告诉你，11月你的lucky day是%d号\n",luckyday);
     
     return 0;
 }