实验二

任务1

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

#define N 5 
#define N1 374
#define N2 465
int main(){
    int number;
    int i;
    srand(time(0));
    for(i=0;i<N;i++){
        number=rand()%(N2-N1+1)+N1;
        printf("202383290376%04d\n",number);
    }
    return 0;
}

line17功能: 输入[N1,N2]之间随机数字
功能：学号尾号随机抽取学生



任务2

#include <stdio.h>
int main (){
    char m;
    while(scanf("%c",&m)!=EOF){
        if(m=='r') printf("stop!\n");
        else if(m=='g')    printf("go go go\n");
        else if (m=='y') printf("wait a minute\n");
        else printf("something must be wrong");
    }
}

任务3

#include <stdio.h>
#include <stdlib.h>
int main (){
    int a,i=1,n;
    printf("猜猜哪一天是你的lucky day\n");
    printf("开始咯"); 
    a=rand()%30+1; 
     for(i=1;i<=3;i++){
         scanf("%d",&n);
         if(n==a){
             printf("猜中了");
             break; 
         }
         if(n>a){
             printf("你猜的日期晚了，你的lucky day已经过了\n"); 
             continue;
         }
         if(n<a){
             printf("你猜的日期早了，你的lucky day还没到呢\n");
             continue;
         } 
     }
     if(i>3){
         printf("次数用完了，你的lucky day是%d",a);
     }
}

实验4

#include <stdio.h>
int main (){
    int a,n;
    double t,s;
    while(scanf("%d",&n)!=EOF&&scanf("%d",&a)){
        t=0;
        s=0;
        for(int i=1;i<=n;i++){
            t=a+t;
            s=s+i*1.0/t;
            a=a*10; 
        } 
        printf("%f",s);
        printf("\n"); 
    }
}

任务5

#include <stdio.h>
int main (){
    int n,i=1,s;
    scanf("%d",&n);
    for(i=1;i<=n;i++){
        for(int j=1;j<=i;j++){
            s=i*j;
            printf("%dx%d=%d\t",i,j,s);
        }
        printf("\n"); 
    }
}

实验6

#include <stdio.h>
int main (){
    int a=1,b=1,c,n,m,i=1;
    scanf("%d",&n);
   m=n;
    for(i=1;i<=n;i++){
        for(a=1;a<i;a++){
            printf("      ");
        } 
        for(b=1;b<=2*m-1;b++){
             printf(" O ");
            printf("   ");
        }
        printf("\n");
        for(a=1;a<i;a++){
            printf("      ");
        } 
        for(b=1;b<=2*m-1;b++){
            printf("<H>");
            printf("   ");
    }
    printf("\n");
    for(a=1;a<i;a++){
            printf("      ");
        } 
    for(b=1;b<=2*m-1;b++){
            printf("I I");
            printf("   ");
    }
    printf("\n");
    m--;
}
}