普通类和多态分别实现计算器

最新推荐文章于 2025-12-15 09:15:21 发布

原创最新推荐文章于 2025-12-15 09:15:21 发布 · 113 阅读

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#c++

文章展示了如何使用C++编写一个简单的计算器程序，首先通过普通类实现基础的加减乘除功能，然后通过引入多态和抽象类的概念，创建不同的计算器子类，以更灵活地处理不同类型的运算。

普通类实现计算器

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

//普通类写法
class Calculator
{
public:
	int getResult(string oper)
	{
		if (oper == "+")
		{
			return m_num1 + m_num2;
		}
		else if(oper == "-")
		{
			return m_num1 - m_num2;
		}
		else if (oper == "*")
		{
			return m_num1 * m_num2;
		}
		else if (oper == "/")
		{
			return m_num1 / m_num2;
		}
	}

	int m_num1;
	int m_num2;
};


void test01()
{
	//创建计算器对象
	Calculator c;
	c.m_num1 = 20;
	c.m_num2 = 10;

	cout << c.m_num1 << " + " << c.m_num2 << " = " << c.getResult("+") << endl;
	cout << c.m_num1 << " - " << c.m_num2 << " = " << c.getResult("-") << endl;
	cout << c.m_num1 << " * " << c.m_num2 << " = " << c.getResult("*") << endl;
	cout << c.m_num1 << " / " << c.m_num2 << " = " << c.getResult("/") << endl;
}

int main() {

	test01();

	system("pause");
	return 0;
}

如果要增加功能需要修改源码

多态

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


//多态实现计算器
//计算器的抽象类
class AbstractCalculator
{
public:
	virtual int getResult()
	{
		return 0;
	}

	int m_num1;
	int m_num2;
};

//加法计算机器类
class AddCalculator:public AbstractCalculator
{
	int getResult()
	{
		return m_num1 + m_num2;
	}
};

//减法计算器类
class SupCalculator :public AbstractCalculator
{
	int getResult()
	{
		return m_num1 - m_num2;
	}
};

//乘法计算器类
class MulCalculator :public AbstractCalculator
{
	int getResult()
	{
		return m_num1 * m_num2;
	}
};

//除法计算器类
class DivCalculator :public AbstractCalculator
{
	int getResult()
	{
		return m_num1 / m_num2;
	}
};

void test02()
{
	//多态使用条件：父类的指针或引用指向子类对象

	//加法运算
	AbstractCalculator* a = new AddCalculator;
	a->m_num1 = 20;
	a->m_num2 = 10;
	cout << a->m_num1 << " + " << a->m_num2 << " = " <<a->getResult()<< endl;
	delete a;

	//减法运算
	AbstractCalculator* b = new SupCalculator;
	b->m_num1 = 20;
	b->m_num2 = 10;
	cout << b->m_num1 << " - " << b->m_num2 << " = " <<b->getResult()<< endl;
	delete b;

	//乘法运算
	AbstractCalculator* c = new MulCalculator;
	c->m_num1 = 20;
	c->m_num2 = 10;
	cout << c->m_num1 << " * " << c->m_num2 << " = " <<c->getResult()<< endl;
	delete c;

	//除法运算
	AbstractCalculator* d = new DivCalculator;
	d->m_num1 = 20;
	d->m_num2 = 10;
	cout << d->m_num1 << " / " << d->m_num2 << " = " <<d->getResult()<< endl;
	delete d;

}

int main() {

	test02();

	system("pause");
	return 0;
}