实验2 c语言分支与循环基础应用编程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++;
    }
    return 0;
}

问1：生成包括N1到N2的随机数，即计科11，12班的学生学号

问2：生成包括1到N3的随机数，即奇安信班的学生学号

问3：随机专业后随机点名该专业的学生

#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;
}

#include<stdio.h>
int main(){
    char a;

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


    }
    return 0;
}

#include<stdio.h>
int main(){
    printf("输入一天内的开销,输入-1时终止:\n");
    double a=0,max=0,min=1000000,sum=0;

    while(a!=-1){
        scanf("%lf",&a);
        if(a==-1)
            break;
        
        if(max<a)
            max=a;
        else if(min>a)
            min=a;
        sum=sum+a;
    }
            
    
    printf("一天总开销:%lf\n",sum);
    printf("最高一笔开销:%lf\n",max);
    printf("最低一笔开销:%lf\n",min);
    return 0;
} 

#include<stdio.h>
int main(){
    int a,b,c,d;
    
    while(scanf("%d%d%d",&a,&b,&c)!=EOF){

        if(b>a&&b>c){
            d=a;a=b;b=d;}
        else if(c>a&&c>b){
            d=a;a=c;c=d;}
        

        if(a*a==b*b+c*c)
            printf("直角");
        else if(a>=b+c)
            printf("不能构成");
        else if(b==c&&a==b)
            printf("等边");
        else if(b==c)
            printf("等腰");
        else
            printf("普通");
    }
    return 0;
} 

#include <stdio.h>
#include <stdlib.h>
int main(){
    printf("哪一天是lucky day呢(1~30)？\n");
    printf("3次机会~\n");
    int a,b,n=0;
    
    srand(time(NULL));
    
    a=rand()%30+1;

    while(n!=3){
        scanf("%d",&b);
        if(b<a)
            printf("早了，还没到~\n");
        else if(b>a)
            printf("晚了，再早点~\n");
        else{
            printf("wow,猜中！\n");
            return 0;
        } 
        printf("再猜(1~30):");
        
        n++;
    }
    printf("次数用尽，你的lucky day是%d号哦~",a);
    return 0;    
}