变量自动跟踪：在变量设置为相同的旧值时调用一个函数，在变量设置为新值时调用另一个函数

如何解决变量自动跟踪：在变量设置为相同的旧值时调用一个函数，在变量设置为新值时调用另一个函数

我想知道在C ++中自动跟踪变量的最佳方法是什么，因此当变量设置为相同的旧值时我们调用一个函数，而当变量设置为新的值时我们调用另一个函数。例如，

#include <iostream>

class A{
public: 
    A();
    virtual ~A();
    bool isActive = false;
    
    void IsActiveChanged();
    void IsActiveIsSetToOldValue();

    
};

A::A(){}
A::~A(){}

A::IsActiveChanged(){
    std::cout << " isActive has changed: isActive Now =  " << isActive << "\n";
}

A::IsActiveIsSetToOldValue(){
    std::cout << " isActive has set to the same value: isActive Now and before =  " << isActive << "\n";
}


int main(){
    A *obj = new A();
    obj->isActive = true;   // this would call A::IsActiveChanged()
    obj->isActive = true;   // this would call A::IsActiveIsSetToOldValue()
    obj->isActive = false; // this would call A::IsActiveChanged()

    delete obj;
    return 0;
}