判断一个点是否在圆内

#include<stdio.h>
typedef struct myPoint
{
    double x;
    double y;
}myPoint; 
int main()
{
    myPoint point;
    int r;
    printf("请输入一个点的x，y位置：");
    scanf("%lf%lf",&point.x,&point.y);
    printf("请输入一个半径：");
    scanf("%d",&r);
    if(point.x*point.x+point.y*point.y<=r*r)
    {
        printf("在圆内\n");
    }
    else
    {
        printf("不在圆内\n");
    } 
    return 0;
}