How to distinguish function overloading and rewriting in C++

Function overloading allows functions with the same name but different signatures in a class, while function overriding occurs in a derived class when it overrides a function with the same signature in the base class, providing different behavior.

The difference between function overloading and rewriting in C

Function overloading

Function overloading allows the use of different functions with the same name in the same class, as long as their signatures (parameter types and number) are different.

Syntax:

return_type function_name(parameter_types) {
  // 函数体
}

// 另一个重载
return_type function_name(other_parameter_types) {
  // 另一个函数体
}

Practical case:

Consider a class named AreaCalculator, It calculates the area of ​​different shapes:

class AreaCalculator {
public:
  double Area(double radius) {
    return M_PI * radius * radius;
  }

  double Area(double length, double width) {
    return length * width;
  }

  double Area(int numOfSides, double sideLength) {
    // 正多边形的面积公式
    // ... 省略后面代码
  }
};

Here, the Area function is overloaded to receive a different number and type of arguments, allowing different areas to be calculated based on the shape type.

Function overriding

Function overriding occurs in a derived class when it overrides a function in the base class with the same signature (name and parameter types). Overridden functions in derived classes often behave differently than functions in base classes.

Syntax:

class DerivedClass : public BaseClass {
public:
  // 重写基类中的函数
  return_type function_name(parameter_types) {
    // 重写的函数体
  }
};

Practical case:

Consider a base class named Shape , which defines a Draw function to draw shapes:

class Shape {
public:
  virtual void Draw() {
    // 绘制通用形状
    // ... 省略后面代码
  }
};

Derived classes Circle can override the Draw function to specifically draw circles:

class Circle : public Shape {
public:
  void Draw() override {
    // 绘制圆形
    // ... 省略后面代码
  }
};

By overriding, the Draw function of the Circle class will override the Draw function of the Shape class, and Provides a more specific drawing implementation.

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