实验2

任务一

源代码

#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;
}

回答问题

问题1：随机生成一个397-476之间的数并赋值给random_no

问题2：随机生成一个1-21之间的数并赋值给random_no

问题3：生成五个随机学号

任务二

#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;
}

任务三

#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;
}

任务四

源代码

#include <stdio.h>

int main() {
    double money, max = 0, min = 1000000, total = 0;

    printf("输入今日开销，直到输入-1终止：\n");
    while (1) {
        scanf("%lf", &money);
        if (money == -1) {
            break;
        }
        if (money > max) {
            max = money;
        }
        if (money < min) {
            min = money;
        }
        total += money;
    }

    printf("今日最高一笔开销：%.1lf元\n", max);
    printf("今日最低一笔开销：%.1lf元\n", min);
    printf("今日累计消费总额：%.1lf元\n", total);

    return 0;
}

任务五

源代码

#include<stdio.h>
#include<math.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 == b && b == c) {
            printf("等边三角形\n");
        }
        else if ((a == b || b == c || a == c) && !(a == b == c)) {
            printf("等腰三角形\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 {
            printf("普通三角形\n");
        }
    }
    return 0;
}

任务六

源代码

#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;
    }