第九次作业

1

#include<stdio.h>

#include<stdlib.h>

#include<time.h>

int main(){

       int a,b,c;

       srand((unsigned)time(NULL));

       a=rand();

       b=a%100;

       while(b!=c)

       {

              printf("请输入一个0--99的数字:");

              scanf("%d",&c);

              if(b<c)

                     printf("大了点!\n");

              if(b>c)

                     printf("小了点!\n");

       }

       printf("你猜中了!\n");

}

 

2

 

#include<stdio.h>

main(){

 int i,a=1;float sum=0;

 for(i=1;i<=100;i++)

 {

  sum+=a*1.0/i;a=-a;

 

 }

 printf("sum=%f\n",sum);

}

 

3

#include<stdio.h>

main(){

       int s=0,n,b=0,a;

       printf("请输入一个整数");

              scanf("%d",&n);

       for(a=1;a<=n;a++)

       {

              s+=a;

                     b+=5;

       }

       printf("%d",b);

}

 

4

#include<stdio.h>

main(){

        long x;

        int temp=0,num=0;

        printf("请输入一个整数:\n");

        scanf("%ld",&x);

        printf("它的每一位数字是:\n");

        while(x>0)

        {

              printf("%3d",x%10);

              temp=temp*10+x%10;

              x=x/10;

              num++;

         }

         printf("\n它是一个%d位数.\n",num);

         printf("它的逆序是:d\n",temp);

}