C ++从基类修改属性

Question

Okay so this seems so simple and yet it explodes my brain when it doesn't work. Here's a very simple few classes. (In VC++ btw)

class Food
{
protected:
    char maxAmountCarried;
};
class Fruit:Food
{
protected:
     Fruit()
     {
         maxAmountCarried = 8; // Works fine
     }
};
class Watermelon:Fruit
{
protected:
     Watermelon()
     {
          maxAmountCarried = 1; //Food::maxAmountCarried" (declared at line 208) is inaccessible
     }
};

So basically, I wanted fruit, by default, to have a max carrying capacity of 8. Watermelons are much larger so the capacity is changed to 1. However, unfortunately I can't access the property.

It would be so much help if someone could tell me a way to work around this problem.

Thanks in advance :)

Answer 1

In C++, when using class as the class key to define classes, inheritance is private by default. If you want public inheritance, you have to say:

class Fruit : public Food { /* ... */ };

class Watermelon : public Fruit { /* ... */ };

Otherwise, Food::maxAmountCarried becomes private in Fruit and is not accessible from within Watermelon .