Assignment Operator Example, C++ (clang)

Assignment Operator Example

// Example with a Base Class with a default assignment operator
// and a Dervied Class with a crazy user-defined assignment operator.
// Also, why is "myStuff" declared as "protected"?

#include <iostream>
using namespace std;

template<class ItemType>
class BaseClass
{
protected:
	ItemType myStuff;
public:
    void setMyStuff(const ItemType &value) {
        myStuff = value;
    };
    void printMyStuff() const {
        cout << "myStuff = " << myStuff << endl;
    };
};

template<class ItemType>
class DerivedClass : public BaseClass<ItemType>
{
public:
    DerivedClass<ItemType>& operator=(const DerivedClass<ItemType>& rhs) {
        this->myStuff = rhs.myStuff + 1;
        return *this;
    };
};

int main() {
    
    cout << "Instance two BaseClass members, and call the " << endl;
    cout << "default (compiler-generated) assignment operator." << endl;
        
    BaseClass<int> myBaseClass1;
    BaseClass<int> myBaseClass2;
    myBaseClass1.setMyStuff(10);
    myBaseClass1.printMyStuff();
    myBaseClass2.setMyStuff(5);
    myBaseClass2.printMyStuff();
    myBaseClass2 = myBaseClass1; // uses the compiler-generated assignment
    myBaseClass2.printMyStuff();
    
    cout << endl;
    cout << "Instance two DerivedClass members, and call our " << endl;
    cout << "crazy assignment operator." << endl;
    
    DerivedClass<int> myDerivedClass1;
    DerivedClass<int> myDerivedClass2;
    myDerivedClass1.setMyStuff(20);
    myDerivedClass1.printMyStuff();
    myDerivedClass2.setMyStuff(3);
    myDerivedClass2.printMyStuff();
    myDerivedClass2 = myDerivedClass1; // uses our "wrong" assignment operator
    myDerivedClass2.printMyStuff();
     
    /* What do you think will happen with the following code?
    myBaseClass1 = myDerivedClass1;
    myBaseClass1.printMyStuff();
    myDerivedClass2 = myBaseClass2;
    myDerivedClass2.printMyStuff();
    */
    
    /* What happens witht the following code?
    DerivedClass<string> myDerivedClass3;
    myDerivedClass3.setMyStuff("Hello");
    myDerivedClass3.printMyStuff();
    DerivedClass<string> myDerivedClass4;
    myDerivedClass4.setMyStuff("Hola");
    myDerivedClass4.printMyStuff();
    myDerivedClass4 = myDerivedClass3;
    */
    
    return 0;
}


run \| edit \| history \| help	0