实验2

#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));      // 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() % (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;

#include <stdio.h>
#include <math.h>

int main() {
    double a, b, c;
    double delta, p1, p2; // 用于保存中间计算结果

    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;
}

#include<stdio.h>
int main()
{
	char r,g,y,ans;
	
	while(scanf(" %c",&ans) != EOF){
	
	if(ans=='r')
	{
		printf("stop!\n");
	}
	else  if(ans=='g')
		printf("go go go\n");

    else if(ans=='y')
	
		printf("wait a minute\n");
	
	else
	
	printf("something must be wrong...\n");

}
    
	return 0;
}

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

int main()
{
	int k=0,s=0;
	float all,x,max,min;
	printf("输入今日开销，直到输入-1终止："); 
	scanf("%f",&x);
	max=x;
	min=x;

	
	while(x>=0){
		s=s+x;
		k++;
		if(x>max) max=x;
		if(x<min) min=x;
		scanf("%f",&x);
	}
	if(k>0)
	{
		all=s*k;
		printf("今日累计消费总额：%.1lf\n,今日最高一笔开销：%.1lf\n,今日最低一笔开销:%.1lf\n",all,max,min);
	}
	system("pause");
	return 0;
}

#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)
		printf("不能构成三角形\n");
		
		else 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&&c==a)
		printf("等边三角形\n");
		
		else if(a==b||a==c||b==c)
		printf("等腰三角形\n");
		
	
		
		else
		printf("普通三角形\n");
	}
	return 0;
	
}

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

int main()
{
	int luckyDay,guess,maxTries=3;
	srand(time(NULL));
	luckyDay=rand()%30+1;
	printf("开始喽，你有三次机会，猜吧(1~30):");
	for(int i =0;i<maxTries;i++)
	   {
	   scanf("%d",&guess);
	   if(guess<1||guess>30){
	   	printf("输入错误\n");
	   	i--;
	   	continue;
	   }
	   if(guess<luckyDay)
	   printf("你猜的日期早了,你的lucky Day还没到呢\n");
	   else if(guess>luckyDay)
	   printf("你猜的日期晚了，你的lucky Day在前面哦\n");
	   else
	  {
	    printf("哇！猜中了！");
	   return 0; }
}
    printf("很遗憾,你没有猜中。你的luckyDay是%d号。\n",luckyDay);
    return 0;
	
}