Page 93 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes {
num1 = 2;
num2 = 3;
int sum = num1 + num2;
return sum;
}
};

int main()
{
ChildCalculator myChildObj;
int result = myChildObj.add();
cout << result;
return 0;
}
The base class has just two properties and no method; these properties are protected. The derived
class has one method and no property. Inside the derived class, the protected properties of the
base class are used as identifiers. Generally, when a derived class is using a member of a base
class, it is a method of the derived class that is using the member, as in this example. The above
code is OK.

The following code will not compile, because line 2 in the main() function tries to access a
protected member of the base class:

#include <iostream>
using namespace std;
class Calculator
{
protected:
int num1;
int num2;
};
class ChildCalculator: public Calculator

{
public:
int add()
{
num1;
num2 = 3;
int sum = num1 + num2;

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