实验2

实验1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define N 5
#define N1 80
#define N2 35

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() % N1 + 1;
            printf("20256343%04d\n", random_no);
        } else {
            random_no = rand() % N2 + 1;
            printf("20256136%04d\n", random_no);
        }

        cnt++;
    }

    return 0;
}

问题1：生成结果相同

问题2：生成随机学号

实验2

#include <stdio.h>

int main() {
    int choice, quantity;
    float total_price=0 , amount_paid, change;

    while (1) {
        printf("\n自动饮料售卖机菜单:\n");
        printf("1. 可乐 - 3 元/瓶\n");
        printf("2. 雪碧 - 3 元/瓶\n");
        printf("3. 橙汁 - 5 元/瓶\n");
        printf("4. 矿泉水 - 2 元/瓶\n");
        printf("0. 退出购买流程\n");
        printf("请输入饮料编号: ");
        scanf("%d", &choice);

        if (choice == 0)
            break;

        if (choice < 1 || choice > 4) {
            printf("无效的饮料编号，请重新输入。\n");
            continue;
        }

        printf("请输入购买的数量: ");
        scanf("%d", &quantity);

        if (quantity < 0) {
            printf("购买数量不能为负数，请重新输入。\n");
            continue;
        }

        if (choice == 1 || choice == 2)
            total_price += 3 * quantity;
        else if (choice == 3)
            total_price += 5 * quantity;
        else
            total_price += 2 * quantity;

        printf("请投入金额: ");
        scanf("%f", &amount_paid);

        change = amount_paid - total_price;
        printf("本次购买总价: %.2f 元\n", total_price);
        printf("找零: %.2f 元\n", change);

        total_price = 0;
    }

    printf("感谢您的购买，欢迎下次光临！\n");
    return 0;
}

问题1：重置金额

问题2：跳过本次循环

实验3

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

实验4

#include<stdio.h>
int main(){
   double n,max=0,min=20000,sum=0;
   printf("输入今日开销，直到输入-1终止:\n");
   while(1){
       scanf("%lf",&n);
       if(n==-1)
       break;
       sum+=n;
       if(n>max)
       max=n;
       if(n<min)
       min=n;}
    printf("今日累计消费总额:%.1f\n",sum);    
    printf("今日最高的一笔开销:%.1f\n",max);
    printf("今日最低的一笔开销:%.1f\n",min);

   return 0;
}

实验5

#include<stdio.h>
  int main(){
      int a,b,c;
      while (1){
          scanf("%d%d%d",&a,&b,&c);
          if(a+b<=c||b+c<=a||a+c<=b)
          printf("不能构成三角形\n");
          else if(a*a+b*b==c*c||b*b+c*c==a*a||a*a+c*c==b*b)
          printf("直角三角形\n");
          else if(a==b&&b==c)
          printf("等边三角形\n");
          else if(a==b&&b!=c||b==c&&c!=a||a==c&&c!=b)
          printf("等腰三角形\n");
          else
          printf("普通三角形\n");
      }
      return 0;
  }

实验6

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
  int main(){
  int luckyday,guessnum,cnt;
  cnt=0;
  srand(time(NULL));
  luckyday = rand()%30 + 1;
  printf("猜猜2025年11月哪一天是你的lucky day\n");
  printf("开始喽，你有三次机会，猜吧(1~30):");
  while(cnt<3){
  scanf("%d",&guessnum);
  if(guessnum==luckyday)
  printf("哇，猜中了:)\n");
  else if(guessnum>luckyday){
  printf("你猜的日期晚了，你的lucky day在前面哦\n");
  printf("再猜(1~30):");
  cnt++;}
  else{
      printf("你猜的日期早了，你的lucky day还没到呢\n");
      printf("再猜(1~30):");
      cnt++;
  }
  if(cnt>=3)
  printf("次数用光啦。偷偷告诉你，11月你的luckyday是%d号\n",luckyday);
}
return 0;
  }