【C++】类和对象-封装

1.属性和行为作为整体

2.示例2-设计学生类

3.访问权限

4.class和struct的区别

5.成员属性设置为私有

6.设计案例1-立方体类

在main函数前重新补上isSame函数

在Cube类里面添加issamebyclass，利用成员函数判断两个立方体是否相等

自己写的代码：

#include 
using namespace std;

class Cube {
public:	//行为
	void setL(int l) {
		m_L = l;
	}
	int getL() {
		return m_L;
	}

	void setW(int w) {
		m_W= w;
	}
	int getW() {
		return m_W;
	}

	void setH(int h) {
		m_H = h;
	}
	int getH() {
		return m_H;
	}

	int calculateS() {
		return 2 * (m_L * m_W + m_L * m_H + m_H * m_W);
	}

	int calculateV() {
		return m_L * m_W * m_H;
	}

	bool IsSameByClass(Cube& c) {
		if (getL() == c.getL() && getW() == c.getW() && getH() == c.getH()) {
			return true;
		}
		return false;
	}

private://属性
	int m_L, m_W, m_H;
};

bool IsSame(Cube& c1, Cube& c2){
	if (c1.getL() == c2.getL() && c1.getW() == c2.getW() && c1.getH() == c2.getH()) {
		return true;
	}
	return false;
}

int main()
{
	Cube c1;
	c1.setL(10), c1.setW(10), c1.setH(10);
	cout << "c1_L=" << c1.getL() << "\tc1_W=" << c1.getW() << "\tc1_H=" << c1.getH()<<endl;
	cout << "c1_S=" << c1.calculateS() << "\tc1_V=" << c1.calculateV() << endl<<endl;

	Cube c2;
	c2.setL(10), c2.setW(10), c2.setH(10);
	cout << "c2_L=" << c2.getL() << "\tc2_W=" << c2.getW() << "\tc2_H=" << c2.getH() << endl;
	cout << "c2_S=" << c2.calculateS() << "\tc2_V=" << c2.calculateV() << endl << endl;

	bool flag = IsSame(c1,c2);
	if (flag) {
		cout << "两个立方体相等。" << endl << endl;
	}
	else {
		cout << "两个立方体不相等。" << endl<<endl;
	}

	bool flag_2 = c1.IsSameByClass(c2);
	if (flag_2) {
		cout << "BYclass两个立方体相等。" << endl << endl;
	}
	else {
		cout << "BYclass两个立方体不相等。" << endl << endl;
	}


	system("pause");

	return 0;
}

7.设计案例2-点和圆的关系

B站视频链接：
https://www.bilibili.com/video/BV1et411b73Z/?p=105&spm_id_from=333.1007.top_right_bar_window_history.content.click&vd_source=fb8dcae0aee3f1aab700c21099045395

main.cpp

#include 
using namespace std;

#include "circle.h"
#include "point.h"
//class Point {
//public:
//	void setX(float x) {
//		m_X = x;
//	}
//	float getX() {
//		return m_X;
//	}
//
//	void setY(float y) {
//		m_Y = y;
//	}
//	float getY() {
//		return m_Y;
//	}
//	
//private:
//	float m_X, m_Y;
//};

//class Circle {
//public:	//行为
//	void setR(float r) {
//		m_R = r;
//	}
//	float getR() {
//		return m_R;
//	}
//
//	void setCenter(Point center) {
//		m_Center = center;
//	}
//	Point getCenter() {
//		return m_Center;
//	}
//
//private://属性
//	Point m_Center;
//	float m_R;
//};

void isInCircle(Circle& c, Point& p) 
	{
	float r = sqrt(pow(c.getCenter().getX() - p.getX(), 2) +
		pow(c.getCenter().getY() - p.getY(), 2));
		if (pow(c.getR(), 2) < pow(r, 2)) 
		{
			cout << "点在圆外" << endl;
		}
	    else if (pow(c.getR(), 2) == pow(r, 2)) 
		{
			cout << "点在圆上" << endl;
		}
		else if (pow(r, 2) == 0)
		{
			cout << "点是圆心" << endl;
		}
		else
		{
			cout << "点在圆内" << endl;
		}
}

int main()
{
	Point p;
	p.setX(0);
	p.setY(9);
	Point center;
	center.setX(0);
	center.setY(0);
	
	Circle c;
	c.setCenter(center);
	c.setR(2);

	isInCircle(c, p);

	system("pause");

	return 0;
}

point.h

#pragma once
#include 
using namespace std;

class Point {
public:
	void setX(float x);
	float getX();

	void setY(float y);
	float getY();

private:
	float m_X, m_Y;
};

point.cpp

#include "point.h"


	void Point::setX(float x) {
		m_X = x;
	}
	float Point::getX() {
		return m_X;
	}

	void Point::setY(float y) {
		m_Y = y;
	}
	float Point::getY() {
		return m_Y;
	}

circle.h

#pragma once
#include 
using namespace std;
#include "point.h"

class Circle {
public:	//行为
	void setR(float r);
	float getR();

	void setCenter(Point center);
	Point getCenter();

private://属性
	Point m_Center;
	float m_R;
};

circle.cpp

#include "circle.h"



	void Circle::setR(float r) {
		m_R = r;
	}
	float Circle::getR() {
		return m_R;
	}

	void Circle::setCenter(Point center) {
		m_Center = center;
	}
	Point Circle::getCenter() {
		return m_Center;
	}