实验2

task.1

#include <stdio.h>
#include <stdio.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;
}

问题1：从N1到N2间选择一个数字

问题2：从0-21间选个数字

问题3：随机抽取学生学工号

task2

#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;
}

task3

#include <stdio.h>

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

task4

#include <stdio.h>

int main()
{
    double a,total,max,min;
    max=0;
    min=20000;
    total=0;
    while(scanf("lf",&a)!=EOF&&a!=-1)
    {
        if(a>max)
        {
            max=a;
        }
        if(a<min)
        {
            min=a;
        }
         total=total+a;
    }
    printf("最大开销=%lf\n",max);
    printf("最低开销=%lf\n",min);
    printf("今日累计消费总和=%lf\n",total);
    
    return 0;
}

 task.5

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

task.6

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



int main(){
    int luckyday = rand() % 30 + 1;
    int day;
    int n = 0;
    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（1~30）\n");
    while(scanf("%d", &day)!=EOF){
        if(day==luckyday){
            printf("哇，猜中了\n");
            break;
            }
        if(day>luckyday){
            printf("你猜的日期晚了,你的lucky day在前面哦\n");
            n++;
            }
        else if(day<luckyday){
            printf("你猜的日期早了，你的lucky day还没到哦\n");
            n++;
            }
        if(n==3){
            printf("次数用光啦，偷偷告诉你，11月你的lucky day是%d号\n",luckyday);
            break;
            }
        }
    return 0;
    }