 
										
					
	
when i want to ask anyone,i will ask myself first.
我给你改改吧

#include <stdio.h>
#include <conio.h>
#include <math.h>
void main()
{
   float x,y,m=0.000001,r[4],h=0;
   int i;
   printf("please input(x,y):\n");
   scanf("%f%f",&x,&y);
   r[0]=(x-2)*(x-2)+(y-2)*(y-2);
   r[1]=(x-2)*(x-2)+(y+2)*(y+2);
   r[2]=(x+2)*(x+2)+(y-2)*(y-2);
   r[3]=(x+2)*(x+2)+(y+2)*(y+2);
   for(i=0;i<4;i++)
    if(r[i]-1<=m)
      h=10-sqrt(r[i])*10;
   printf("%f\n",h);
   getch();
}
