实验2

实验1

#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;
}

line 21代码功能：产生一个随机数，范围在397-476之间

line25代码功能：产生一个随机数，范围在1-21之间

程序作用：输出学号，总共输出五次，若学号前缀为20248329，则随机397-476之间的一个值，补零后接在前缀后输出；若学号前缀为20248395，则随机1-21之间一个值，补零后输出

实验2

#include<stdio.h>
#include<math.h>
int main()
{
    double a,b,c;
    double delta,p1,p2;
    while(scanf("%lf%lf%lf",&a,&b,&c)!=0)
    {
        if(a==0)
        {
        printf("a=0,invalid input");
        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;
}

实验3

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

实验4

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main() {
    double min = 0.00;
    double max = 0.00;
    double a = 0.00;
    double cost;
    printf("输入今日开销，直至输入-1终止:\n");
    while (scanf("%lf", &cost) != EOF)
    {
        if (cost == -1)
        {
            break;
        }
        a = a + cost;
        if (cost> max)
        {
            max = cost;
        }
        if (min==0)
        {
            min = cost;
        }
        if (cost< min)
        {
            min = cost;
        }
    }
    printf("今日累计消费总额：%.1lf", a);
    printf("今日最高一笔开销：%.1lf", max);
    printf("今日最低一笔开销：%.1lf", min);
    return 0;
}

实验5

#include<stdio.h>
int main()
{
    int a, b, c;
    while (scanf("%d%d%d", &a, &b, &c) != EOF)
    {
        if ((a + b > c) && (a + c >b) && (b + c > a))
        {
            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 || b == c || c == a)
            {
                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("无法构成三角形\n");
        }
    }
    return 0;
}

实验6

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main() {
  int a,b;
  int choice=3;
  srand(time(NULL));
  a = rand()%30 +1;
  printf("猜猜2024年11月那一天会是你的幸运日\n开始喽，你只有三次机会，猜吧（1~30):");
  while(choice > 0){
    scanf("%d",&b) ;
    if(b == a){
        printf("哇，猜中了:)");
        return 0;
    }
    else if(b < a){
        printf("你猜的日期早了\n再猜(1~30)：");
    }
    else if(b>a){
        printf("你猜的日期晚了\n再猜(1~30)：");
    }
    choice--;
  }
  printf("次数用光啦，偷偷告诉你，11月你的幸运日是%d号",a);
    return 0;
}