实验作业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)); // 以当前系统时间作为随机种子
  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;
}

作用：调节seed的值；

功能：随机生成不重复的学生编号。

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;
}

去掉total_price = 0,会使程序报错，因为后续对total_price 进行运算但total_price没有定值；

continue的作用为跳过本循环剩余语句，重新输入编号和数量。

实验3

#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");
    }
      
    
    
    }
 } 

实验4

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
    float money,max,min,sum;
    max = sum = 0.0;
    min = 20000.0;
    printf("请输入今日开销，知道输入-1终止：\n");
    while (scanf("%f", &money),money!=-1)
    {
        sum += money;
        if (max < money)
            max = money;
        if (min > money)
            min = money;

    }
    printf("今日累计消费总额：%.1f\n",sum);
    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;
}

 

 

实验5

#define _CRT_SECURE_NO_WARNINGS
#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)
        {
            if (a* a + b * b == c * c || a * a + c * c == b * b || b * b + c * c == a * a)
            {
                printf("直角三角形\n");
            }
            else if (a == b || a == c || b == c)
            {
                if (a == b&&b==c&&a==c)
                {
                    printf("等边三角形\n");
                }
                else
                {
                    printf("等腰三角形\n");
                }
            }
            else
            {
                printf("普通三角形\n");
            }
        }
        else
        {
            printf("不能构成三角形\n");
        }
    }

    return 0;
}

实验6

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
    int day,n = 0;
    srand(time(NULL));
    int num = rand() % 30 + 1;
    printf("猜一猜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）：\n");
    while (n < 3)
        {
            scanf("%d", &day);
            if (day > num)
            {
                printf("你猜的日期晚了，你的lucky day在前面哦\n");
                
            }
            else if (day < num)
            {
                printf("你猜的日期早了，你的lucky day还没到呢\n");
                
            }
            else
            {
                printf("哇，猜中了");

                break;
            }
            n++;
            if (n < 3) 
            {
                printf("再猜（1-30）");
            }
            else
            {
                printf("次数用完啦。偷偷告诉你，11月你的lucky day是%d号", num);
            }
            
            
        }
    
    
    return 0;
}