编辑代码

#include <stdio.h>
#define N 15
int main () {
   int a[N];
   int i,j,m,n,mid,num;
   int p=1;
   printf("从大到小依次输入15个数：");
   for(i=0;i<N;i++)
   scanf("%d",&a[i]);

   m=0;
   n=N-1;
   

   printf("input the number:");
   scanf("%d",&num);
   if(num>a[n]&&num<a[m])
   {
       p=0;
       printf("输入错误，请重新运行");
   }
   
   while(m<=n&&p==1)
   {
       mid=(m+n)/2;
       if(num==a[mid])
       {
           p=0;
           printf("%d是第%d个数字",num,mid+1);
       }
       else if(num>a[mid])
       {
           m=mid+1;
       }
       else if(num<a[mid])
       {
           n=mid-1;
       }
   }
   if(p)
   {
       printf("未找到该数字");
   }
   
	return 0;
}