C++深入探索类和对象之封装及class与struct的区别

#include<iostream>
using namespace std;
//class代表设计一个类，后面跟着的是类名
class taiAngle
{
public:  //访问权限  公共的权限
	//属性
    int m_a;//直角边a
    int m_b;//直角边b
	//行为
	//获取三角形面积
	double calculate()
	{
		return (m_a*m_b)/2;
	}
};
int main() {
 
	//通过三角形类，创建三角形的对象
	// c1就是一个具体的三角形
	taiAngle c1;
	c1.m_a = 10; //给三角形两边进行赋值操作
    c1.m_b = 10;
	cout << "三角形的面积为： " << c1.calculate() << endl;//调用方法
	system("pause");
	return 0;
}

//学生类
class Student {
public:
	void setName(string name) {
		m_name = name;
	}
	void setID(int id) {
		m_id = id;
	}
	void showStudent() {
		cout << "name:" << m_name << " ID:" << m_id << endl;
	}
private:
	string m_name;
	int m_id;
};
int main() {
	Student stu;
	stu.setName("马可波罗");
	stu.setID(250);
	stu.showStudent();
	system("pause");
	return 0;
}
 

class Person
{
	//姓名  公共权限
public:
	string m_Phone;
	//手机  保护权限
protected:
	string m_Phone;
	//银行卡密码  私有权限
private:
	int m_Password;
public:
	void display();
};
void Person::display()
{
	m_Name = "张三";
	m_Phone = "华为";
	m_Password = 123456;
}
int main() {
	Person p;
	p.m_Name = "李四";
	//p.m_Phone = "iPhone 13";  //保护权限类外访问不到
	//p.m_Password = 123;     //私有权限类外访问不到
	system("pause");
	return 0;
}

class C1
{
	int  m_A; //默认是私有权限
};
struct C2
{
	int m_A;  //默认是公共权限
};
int main() {
	C1 c1;
	c1.m_A = 10; //错误，访问权限是私有
	C2 c2;
	c2.m_A = 10; //正确，访问权限是公共
	system("pause");
	return 0;
}

class Person {
public:
	//姓名设置可读可写
	void setName(string name) {
		m_Name = name;
	}
	string getName()
	{
		return m_Name;
	}
 
	//获取年龄 
	int getAge() {
		return m_Age;
	}
	//设置年龄
	void setAge(int age) {
		if (age < 0 || age > 150) {
			cout << "你个大乌龟!" << endl;
			return;
		}
		m_Age = age;
	}
	//情侣设置为只写
	void setLover(string lover) {
		m_Lover = lover;
	}
private:
	string m_Name; //可读可写  姓名
	int m_Age; //只读  年龄
	string m_Lover; //只写  爱人
};
int main() 
{
	Person p;
	//姓名设置
	p.setName("张三");
	cout << "姓名： " << p.getName() << endl;
	//年龄设置
	p.setAge(50);
	cout << "年龄： " << p.getAge() << endl;
	//爱人设置
	p.setLover("阿尼亚");
	//cout << "爱人： " << p.m_Lover << endl;  //只写属性，不可以读取
	system("pause");
	return 0;
}

#include<iostream>
using namespace std;
//案例1 判断两个立方体是否相等
class Cube
{
public:
	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 Area(int a, int b, int c)
	{
		return 2 * (a * b + a * c + b * c);
	}
	int 体积(int a, int b, int c)
	{
		return a * b * c;
	}
	bool isSameByClass(Cube& x)
	{
		if (x.getH() == m_H && x.getL() == m_L && x.getW() == m_W)
		{
			return true;
		}
		else {
			return false;
		}
	}
private:
	int m_L;
	int m_W;
	int m_H;
};
//利用全局函数判断，两个立方体是否相等
bool isSame(Cube& c1, Cube& c2)
{
	if (c1.getL() == c2.getL() && c1.getW() == c2.getW() && c1.getH() == c2.getH())
	{
		return true;
	}
	else
	{
		return false;
	}
}
int main()
{
	Cube c1;
	c1.setH(10);
	c1.setL(10);
	c1.setW(10);
	Cube c2;
	c2.setH(10);
	c2.setL(10);
	c2.setW(10);
	cout << "面积为：" << c1.Area(c1.getH(), c1.getH(), c1.getL()) << endl;
	cout << "体积为：" << c1.体积(c1.getH(), c1.getH(), c1.getL()) << endl;
	//利用成员函数判断立方体
	if (c1.isSameByClass(c2))
	{
		cout << "两个立方体相等" << endl;
	}
	else {
		cout << "两个立方体不相等" << endl;
	}
	//利用全局函数判断
	bool ret = isSame(c1, c2);
	if (ret)
	{
		cout << "两个立方体相等" << endl;
	}
	else {
		cout << "两个立方体不相等" << endl;
	}
}