小朋友学C++（8）：继承

#include <iostream>
using namespace std;
class Animal
{
protected:
    float weight;
public:
    void setWeight(float w) 
    {
        weight = w;
    }
    float getWeight()
    {
        return weight;
    }
    void breathe()
    {
        cout << "breathing..." << endl; 
    }   
};
class Dog : public Animal
{
private:
    int legs;
public:
    void setLegs(int number)
    {
        legs = number;  
    }
    int getLegs()
    {
        return legs;    
    }
    void bark()
    {
        cout << "wang! wang!" << endl;
    }   
};
int main(int argc, char** argv)
{
    Dog dog;
    dog.setWeight(12.5);
    dog.setLegs(4);
    cout << "The dog's weight is " << dog.getWeight() << "kg" << endl;
    cout << "The dog has " << dog.getLegs() << " legs" << endl; 
    dog.breathe();
    dog.bark();
    return 0;
}

The dog’s weight is 12.5kg
The dog has 4 legs
breathing...
wang! wang!