C++学习笔记——类的调用

类与类之间可以继承，也可以调用，下面的代码是演示Circle类是如何调用Point类的

#include<iostream>
using namespace std;
class Point{
    
    
	private:
		int x, y;
	public:
		void initPoint(int a, int b);
		double getX(){
    
    return x;};
		double getY(){
    
    return y;};
		void print();
};
void Point::initPoint(int a, int b){
    
    
	x=a;
	y=b;
}
void Point::print(){
    
    
	cout<<'['<<x<<','<<y<<']';
}

class Circle{
    
    
	private:
		double r;
		Point c;
	public:
		void initCircle(double R, Point C);
		double getR(){
    
    return r;};
		Point getC(){
    
    return c;};
		double area(){
    
    return 3.14*r*r;};
		void print();
};
void Circle::initCircle(double R, Point C){
    
    
	r=(R>=0?R:0);
	c=C;
}
void Circle::print(){
    
    
	cout<<"c=";
	c.print();
	cout<<";r="<<r<<endl;
}

int main(){
    
    
	Point myPoint;
	Circle myCircle;
	myPoint.initPoint(2,2);
	myCircle.initCircle(2.0,myPoint);
	myCircle.print();
	cout<<"center=";
	myCircle.getC().print();
	cout<<endl;
	cout<<"area="<<myCircle.area()<<endl;
	return 0;
}

运行结果：
c=[2,2];r=2
center=[2,2]
area=12.56