【C++】多态案例— —计算器类

**多态案例——计算器类**

在面向对象编程中，多态是指一个方法或函数可以有多种不同的行为，这取决于它的上下文。计算器类是一个经典的例子，它可以实现多态。

### 计算器类设计我们将设计一个简单的计算器类，支持基本的四则运算：加、减、乘、除。

#### 基本结构

cppclass Calculator {
public:
 virtual double calculate(double num1, double num2) =0; // 抽象方法};

cppclass Adder : public Calculator {
public:
 double calculate(double num1, double num2) override {
 return num1 + num2;
 }
};

class Subber : public Calculator {
public:
 double calculate(double num1, double num2) override {
 return num1 - num2;
 }
};

class Multiplier : public Calculator {
public:
 double calculate(double num1, double num2) override {
 return num1 * num2;
 }
};

class Divider : public Calculator {
public:
 double calculate(double num1, double num2) override {
 if (num2 ==0) {
 throw std::runtime_error("Cannot divide by zero!");
 }
 return num1 / num2;
 }
};

cppint main() {
 Calculator* adder = new Adder();
 Calculator* subber = new Subber();
 Calculator* multiplier = new Multiplier();
 Calculator* divider = new Divider();

 double result1 = adder->calculate(5,3);
 double result2 = subber->calculate(10,4);
 double result3 = multiplier->calculate(7,2);
 double result4 = divider->calculate(9,3);

 std::cout << "Add: " << result1 << std::endl;
 std::cout << "Subtract: " << result2 << std::endl;
 std::cout << "Multiply: " << result3 << std::endl;
 std::cout << "Divide: " << result4 << std::endl;

 delete adder;
 delete subber;
 delete multiplier;
 delete divider;

 return0;
}