C语言判断坐标是否在圆上

大神帮我解答一下。

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<ctype.h>
#include<stdlib.h>
#define N 10
#define M 80
int insert(char ss[][M])
{int i,j,len,sum=0;
for(i=0;i<N;i++)
{len=strlen(ss[i]);
sum=sum+len;
if(len<10)
{for(j=len;j>0;j--)
ss[i][j]=ss[i][j-1];
ss[i][0]=len+48;
ss[i][len+1]='\0';
}
else
{for(j=len+1;j>1;j--)
ss[i][j]=ss[i][j-2];
ss[i][0]=len/10+48;
ss[i][1]=len%10+48;
ss[i][len+2]='\0';
}
}
//printf("sum=%d\n",sum);
return sum/N;
}
int delstr(char ss[][M],int k)
{int i,j,n=N,m;
for(i=0;i<N;i++)
{m=0;
for(j=0;ss[i][j];j++)
if(ss[i][j]>='A'&&ss[i][j]<='Z'||ss[i][j]>='a'&&ss[i][j]<='z')
m++;
if(m>=k)
{for(j=i;j<N;j++)
strcpy(ss[j],ss[j+1]);
n--;
i--;
}

}
printf("n=%d\n",n);
return n;
}
int main()
{
char ss[N][M]={"Manufacturing","History","Trade","Construction",
"Administrative","Policies","Spotrs","Infrastruct",
"EconnomyOA","DeliciousFoods"};
int i,k,p;
k=insert(ss);
printf("k=%d\n",k);
p=delstr(ss,k);
printf("处理后结果:\n");
for(i=0; i<p; i++)
puts(ss[i]);
return 0;
}

t代码都有了，你想问什么？

你只需判断 坐标离 圆心的距离 和半径之间的关系，很难吗？