實驗 2

task 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)); // 以當前系統時間作為隨機種子
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;
}

問題1：使得生成的20248329（xxxx）範圍在11 12班的學號內

問題2：使得生成的202483295（xxxx）範圍在奇安信班的學號內

問題3：該程式實現了隨機抽取11.12班.奇安信班的同學回答問題

task 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 = 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;
}

task 3

#include <stdio.h>

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

task 4

#include<stdio.h>
int main(){
    printf("輸入今日開銷，直到輸入-1終止："); 
    double a[100];
    int i;
    double sum=0;
    int count=0;
    for(i=0;i<100;i++){
        scanf("%lf",&a[i]);
        sum+=a[i];
        if(a[i]==-1){
            break;
        }
        count++;
    }
        double temp1=0;
        double temp2=a[0];
    for(i=0;i<count;i++){
        
        if(a[i]>temp1){
            temp1=a[i];
            
        }
    }
    
    for(i=1;i<count;i++){
        if(a[i]<temp2&&a[i]!=-1){
            temp2=a[i];
        }
    }
    printf("今日累計消費總額%.1f\n",sum); 
    printf("今日最高一筆開銷%.1f\n",temp1);
    printf("今日最低一筆開銷%.1f\n",temp2);
    
    return 0;
}

task 5

#include<stdio.h>
int main(){
    int a,b,c;
    while(scanf("%d%d%d",&a,&b,&c)!=EOF){
        if((a+b>c)&&(b+c>a)&&(a+c>b)){
            if(a==b&&b==c&&a==c){
                printf("等邊三角形\n");
                
            }
            else if(a==b||b==c||a==c) {
                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"); 
            }
            
        
        }
        else{
            printf("不能構成三角形\n");
        }
        
    }
}

task 6

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

int main() {
    printf("猜猜 2024 年 11 月哪一天會是你的 luckday\n");
    printf("開始嘍，你有三次機會，猜吧（1~30）：\n");

    srand(time(NULL));
    int luckyday = rand() % 30 + 1;
    int guess;
    int attempts = 0;

    while (attempts < 3) {
        scanf("%d", &guess);
        if (guess < luckyday) {
            printf("你猜的日期早了，你的 luckyday 還沒到呢\n");
            if (attempts < 2) {
                printf("再猜\n");
            }
        } else if (guess > luckyday) {
            printf("你猜的日期晚了，你的 luckyday 在前面哦\n");
            if (attempts < 2) {
                printf("再猜\n");
            }
        } else if (guess == luckyday) {
            printf("哇，猜中了");
            break;
        }
        attempts++;
    }

    if (attempts == 3) {
        printf("次數用光啦。偷偷告訴你，11 月你的 luckyday 是 %d 號", luckyday);
    }

    return 0;
}