实验2

test 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));

    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++;

    }
    system("pause");

    return 0;

}

问题1 确保生成的数字在397至476之间

问题2 确保生成的数字在1至21之间

问题3 随机生成5个学号

test2

#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=%.2gx2=%.2g\n",p1+p2,p1-p2);
        else{
            printf("x1=%.2g+%.2gi,",p1,p2);
            printf("x2=%.2g+%.2gi\n",p1,p2);
        }
        
    }
    return 0;
}

test3

#include <stdio.h>

int main(){
    char zimu;

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

    return 0;

}

 test4

#include <stdio.h>

int main() {
    float expense,min,max,total;
    total = 0, max = 0, min = 20000;

    printf("输入今日开销，直到输入-1终止：\n");
    while (1) {
        scanf_s("%f", &expense);

        if (expense == -1)
            break;

        if (expense > max)
            max = expense;
        if (expense < min)
            min = expense;

        total += expense;

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

    return 0;
}

test5

#include <stdio.h>

int main() {
    int a, b, c;
    while (scanf_s("%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 && a == c && 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;
}

test6

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

int main() {
    int  luckyday, guess, i=1;
    srand(time(NULL));

    luckyday = rand() % 30 + 1;

    printf("猜猜2024年11月哪一天会是你的lucky day\n\n");
    printf("开始咯，你有三次机会，猜吧（1~30）：");

    while(i<=3) {
        scanf_s("%d", &guess);
        printf("\n");

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

        else if (guess < luckyday)
            printf("你猜的日期早了，你的luckyday还没到呢\n\n");
        else
            printf("你的日期晚了，你的luckyday在前面哦\n\n");

        i++;

        if(i<=3)
        printf("再猜（1~30):");

    }

    if(i=4)
    printf("次数用光啦。偷偷告诉你，11月你的luckyday是%d号", luckyday);
    

    return 0;
}