用结构体求两个圆的关系

定义一个圆的结构体，给两个圆的圆心和半径分别赋值，判断两个圆的关系（相交、相切、相离、重合）。
#import <Foundation/Foundation.h>
typedef struct
{
    int x;
    int y;
    float r;
} Circle;

void compareCircle(Circle a,Circle b)
{
    float  rr = 0;
    if (a.x>=b.x)//比较点坐标大小，用大数减掉小数；
    {
        int xab = a.x - b.x;
        if (a.y>=b.y)
        {
            int yab = a.y - b.y;
            rr = fabs(sqrt(xab * xab + yab * yab));
        }else
        {
            int yab = b.y - a.y;
            rr = fabs(sqrt(xab * xab + yab * yab));
        }
    }else
    {
        int xab = b.x - a.x;
        if (a.y>=b.y)
        {
            int yab = a.y - b.y;
            rr = fabs(sqrt(xab * xab + yab * yab));
        }
        else
        {
            int yab = b.y - a.y;
            rr = fabs(sqrt(xab * xab + yab * yab));
        }
    }
    if (a.x == b.x && a.y == b.y)
    {
        printf("两个圆重合\n");
    }else if (rr > a.r + b.r)
    {
        printf("两个圆相离\n");
    }else if ((rr ==a.r-b.r)||(rr==b.r-a.r)||(rr=a.r+b.r))
    {
        printf("两个圆相切\n");
    }else
    {
        printf("两个圆相交\n");
    }
}
int main()
{
    Circle c1,c2;
    printf("输入要比较的圆1的坐标及半径：\n");
    scanf("%d%d%f",&c1.x,&c1.y,&c1.r);
    printf("输入要比较的圆2的坐标及半径：\n");
    scanf("%d%d%f",&c2.x,&c2.y,&c2.r);
    compareCircle(c1, c2);
    return 0;
}