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("20248329%04d\n", random_no);
            
        }
        
        
        cnt++;
}

      return 0;
  }

line21功能：生成N1-N2的整数
line25功能：生成N2-N3的整数
程序功能：随机生成学号

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) != 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 = %.2g,x2 = %.2g\n",p1+p2,p1-p2);
            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,",p1,p2);
            }
    }
    return 0;
}

实验3

#include<stdio.h>

int main()
{
    char color;
    while((color = getchar())   !=EOF){
    if (color == 'r'){
    printf("stop!\n");}
    else if (color == 'y'){
    printf("wait a minute\n");}
    else if(color == 'g'){
    printf("go go go\n");}
    else{
    printf("something must be wrong...\n");}
    getchar();
    }
    
    return 0;
}

实验4

#include<stdio.h>

int main()
{
    double expense;
    double max = 0.0;
    double min = 20000.0;
    double totalexpense = 0.0;
    printf("输入今日开销，直到输入-1为止：\n");
    while (scanf_s("%lf", &expense) != EOF && expense != -1)
    {
        if (expense > max)
        {
            max = expense;
        }
        if (expense < min)
        {
            min = expense;
        }
        totalexpense += expense;
    }
    if (max > 0 && min < 20000 && totalexpense > 0)
    {
        printf("今日累计消费：%.1lf\n", totalexpense);
        printf("今日最高开销：%.1f\n", max);
        printf("今日最低消费：%.1f\n", min);
    }
    else
    {
        printf("error\n");
    }
    return 0;
}

实验5
#include<stdio.h>

int main()
{
    int a, b, c;
    while (scanf_s("%d %d %d", &a, &b, &c) != EOF)
    {
        if (a + b <= c || a + c <= b || b + c <= a)
        {
            printf("不能构成三角形\n");

        }
        else {
            if (a == b && b == c) {
                printf("等边三角形");
            }
            else if (a == b || a == c || b == c) {
                if (a * a + b * b == c * c || b * b + c * c == a * a || a * a + c * c == b * b) {
                    printf("等腰直角三角形\n");

                }
                else {
                    printf("等腰三角形\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 { printf("普通三角形\n"); }

            
        }

    }
}

实验6

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

 int main() {
         srand(time(NULL));
         int luckyDay = rand() % 30 + 1;
         int guess;
         int chances = 3;
         printf("猜猜2024年11月哪一天会是你的lucky day\n 开始喽，你有三次机会，猜吧( 1 and 30)：\n");
         while (chances > 0) {
                 scanf_s("%d", &guess);
                 if (guess == luckyDay) {
                         printf("You guessed it right!\n");
                         return 0;
            
        }
        else if (guess < luckyDay) {
                         printf("你猜的日期早了，你的lucky day还没到呢\n");
            
        }
        else {
                         printf("你猜的日期晚了，你的lucky day在前面哦\n");
            
        }
                 chances--;
        
    }
         printf("次数用光啦。偷偷告诉你，11月你的lucky day是%d.\n", luckyDay);
         return 0;
    
}