实验2 C语言分支与循环基础应用编程-1

1、实验任务1

task1.c

#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("20248395%04d\n", random_no);
        }

        cnt++;
    }

    return 0;
}

问题1：line21的功能是为了生成一个N1到N2的随机数

问题2：line25的功能是为了生成一个1到N3的随机数

问题3：这个代码可以生成随机学号

 

 

2、实验任务2

task2.c

#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;
}

 

 

 

3、实验任务3

task3.c

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

int main() {
char x;

while(scanf("%s", &x) != EOF) {
    if (x == 'r')
        printf("stop!\n");
    else if (x == 'g')
        printf("go go go\n");
    else if (x == 'y')
        printf("wait a munite\n");
    else
        printf("something must be wrong...\n");
}

return 0;
}

 

 

4、实验任务4

task4.c

#include <stdio.h>

int main() {
    double expense, total = 0, maxExpense = 0, minExpense = 20000;  

    printf("输入今日开销，直到输入-1 终止：\n");

    while (1) {
        scanf("%lf", &expense);

        if (expense == -1) {
            break;
        }

        total += expense;

        if (expense > maxExpense) {
            maxExpense = expense;
        }

        if (expense < minExpense) {
            minExpense = expense;
        }
    }

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

    return 0;
}

 

 

5、实验任务5

task5.c

#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 == b) && (b == 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) || (b * b + c * c == a * a)) {
                printf("直角三角形\n");
            } else {
                printf("普通三角形\n");
            }
        }
    }

    return 0;
}

 

 

 

6、实验任务6

task6.c

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

int main() {
    int luckyDay, guess, attempts = 3;
    srand(time(NULL)); 
    luckyDay = rand() % 30 + 1; 

    printf("猜猜 2024 年 11 月哪一天会是你的 lucky day\n");
    printf("开始喽，你有三次机会，猜吧(1~30)：");
    while (attempts > 0) {
        
        scanf("%d", &guess);

        if (guess == luckyDay) {
            printf("哇，猜中了:)\n");
            break; 
        } 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");
        }

        attempts--;
        printf("再猜（1~30）："); 
    }

    if (attempts == 0) {
        printf("次数用光啦。偷偷告诉你，11 月你的 lucky day 是 %d 号\n", luckyDay);
    }

    return 0;
}