多态案列-计算器实现

 1、利用普通算法实现计算器类

# include<iostream>
# include<string>

using namespace std;
//分别利用普通的写法和多态的写法实现计算器

//普通写法
class Calculator
{
public:
	int getResult(string oper)
	{
		if (oper == "+")
			return m_numb1 + m_numb2;
		else if (oper == "-")
			return m_numb1 - m_numb2;
		else if (oper == "*")
			return m_numb1 * m_numb2;
	}//如果想扩展新功能 需要扩展源码
	//在真是开发中，提倡开闭原则
	//关闭原则：多扩展进行开发，对修改进行关闭

	int m_numb1;
	int m_numb2;

};

void test01()
{
	Calculator c;
	c.m_numb1 = 10;
	c.m_numb2 = 10;
	cout << c.m_numb1 << "+" << c.m_numb2 << "=" << c.getResult("+") <<