C++基础计算器类_c++计算器类csdn-优快云博客

本文介绍了C++中多态的概念，并通过一个计算器类的案例展示了如何使用抽象基类和派生类实现多态。文章详细讲解了普通计算器类的不足以及多态带来的组织结构清晰、可读性强和易于维护等优点。通过创建不同运算类型的计算器子类，实现了加法、减法和乘法计算器，展示了多态的运用。

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/*
* B站学习--[136 - ]
* day26 学习成果
*/

/*
* 
* 多态原理剖析
* 
* 
* 4.7.2 多态案列一  计算器类
* 
* 
*/

#include<iostream>
#include<string>
using namespace std;

//普通写法 不利于维护 扩展
class Calculator {
public:
	int num1;//操作数1
	int num2;//操作数2

	int getResult(string oper)
	{
		if (oper == "+")
		{
			return num1 + num2;
		}
		else if (oper == "-")
		{
			return num1 - num2;
		}
		else if (oper == "*")
		{
			return num1 * num2;
		}
		else if (oper == "/")
		{
			if (num2 != 0)
				return num1 / num2;
			else
			{
				cout << "除数不能为0" << endl;
				return 0;
			}
		}
	}

};

//多态技术
//多态带来的好处
//1.组织结构清晰
//2.可读性强
//3.对于前期和后期扩展以及维护性高 

//实现计算器的抽象类
class AbstractCalculator {
public:
	int num1;
	int num2;

	virtual int getResult() {
		return 0;
	}
};

//加法计算器类
class Addcalculator :public AbstractCalculator {
public:
	int getResult() {
		return num1 + num2;
	}
};

//减法计算器类
class Subcalculator :public AbstractCalculator {
public:
	int getResult() {
		return num1 - num2;
	}
};

//乘法计算器类
class Mulcalculator :public AbstractCalculator {
public:
	int getResult() {
		return num1 * num2;
	}
};

void test01() 
{
	Calculator c;
	c.num1 = 10;
	c.num2 = 20;

	cout << c.num1 << " + " << c.num2 << " = " << c.getResult("+") << endl;
	cout << c.num1 << " - " << c.num2 << " = " << c.getResult("-") << endl;
	cout << c.num1 << " * " << c.num2 << " = " << c.getResult("*") << endl;
	cout << c.num1 << " / " << c.num2 << " = " << c.getResult("/") << endl;

}

void test02()
{
	//加法运算
	AbstractCalculator* abc = new Addcalculator;
	abc->num1 = 10;
	abc->num2 = 10;

	cout << abc->num1 << " + " << abc->num2 << " = " << abc->getResult() << endl;
	//用完后记得销毁
	delete abc;

	//减法运算
	abc = new Subcalculator;
	abc->num1 = 10;
	abc->num2 = 10;

	cout << abc->num1 << " - " << abc->num2 << " = " << abc->getResult() << endl;
	//用完后记得销毁
	delete abc;

	//乘法运算
	abc = new Mulcalculator;
	abc->num1 = 10;
	abc->num2 = 10;

	cout << abc->num1 << " * " << abc->num2 << " = " << abc->getResult() << endl;
	//用完后记得销毁
	delete abc;

}

int main() 
{
	//test01();
	test02();

	system("pause");

	return 0;
}