成员函数只有double怎么实现呀

Question

#include <iostream>
#include <string>
#include <algorithm>
#include <string>
using namespace std;
class Coordinate {
public:
	Coordinate();
	Coordinate(double xx, double yy); //构造函数，对数据成员进行初始化
	void display(); //显示坐标(x,y)
	void setX(double); //设置 X
	void setY(double); //设置 Y
	double distance(); //计算并返回点到坐标原点的距离
private:
	double x, y;
};
Coordinate::Coordinate() {}
Coordinate::Coordinate(double xx, double yy) {
	x = xx;
	y = yy;
}
void Coordinate::display() {
	cout << x << "," << y;
}
void Coordinate::setX(double) { //这里

}
void Coordinate::setY(double) { //和这里

}
double Coordinate::distance() {
	double d = 0;
	return d = sqrt(x * x + y * y);
}
int main() {
	Coordinate point1(1.0, 1.0);
	double d1 = point1.distance();
	cout << d1 << endl;
	Coordinate point2;
	point2.setX(5.0);
	point2.setY(10.5);
	point2.display();
	return 0;
};

Answer 1

改为如下：

void Coordinate::setX(double xx) { //这里

      x = xx;

}

void Coordinate::setY(double yy) { //和这里

      y = yy;

}