Question

在java中设计一个程序，判断直角坐标系中一个点是否在以（0,0）为圆心以1为半径的圆内？

谢谢谢谢！

Answer 1

public class Coordinate {

public static void main(String[] args) {
double x = 0.5;//测试点横坐标
double y = 0.3;//测试点纵坐标
final double r = 1;//半径为1

boolean isInCircle = isPointInCircle(x, y, r);
System.out.println("点(" + x + "," + y + ")" + (isInCircle? "在": "不在") + "以原点(0,0)为圆心半径为" + r + "的圆内!");
}

private static boolean isPointInCircle(double x, double y, double r) {

//园内的点必须满足x < 1 && y <1并且x*x + y*y < 1
if(Math.abs(x) >= r || Math.abs(y) >= r){
return false;
}

return Math.pow(x, 2) + Math.pow(y, 2) < 1;
}

}
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点(0.5,0.3)在以原点(0,0)为圆心半径为1.0的圆内!

Answer 2

public boolean isInner(double x,double y){
return Math.pow(x*x+y*y, 0.5)<=1;
}