Demo No. 3a Inheritance I </HEAD> <BODY> <H1> <CENTER><B> <FONT SIZE= 4>Inheritance</FONT></B> </CENTER></H1> <H2> <FONT SIZE= 3> Inheritance is achieved by creating new classes from exisiting ones</FONT> </H2> <P><BR> #include <iostream.h><BR> class Base {<BR> private:<BR><BLOCKQUOTE> int private_data_x;<BR></BLOCKQUOTE> public:<BR><BLOCKQUOTE> Base(): private_data_x (0) {}<BR> int Get() { return private_data_x;}<BR> void Set( int i) {private_data_x = i;}<BR></BLOCKQUOTE> };<BR> class Derived: public Base // A new class derived from class Base <BR> {<BR> // This class has no added members of its own<BR> // It simply makes use of the data member via functions <BR>Get & Set<BR> };<BR> void main()<BR> {<BR><BLOCKQUOTE> cout << " Before: " << endl;<BR> // Base class object<BR> Base base;<BR> cout << "Base's private_data_x is : " << base.Get() << endl;<BR> // Derived class object<BR> Derived derived;<BR> cout << "Derived's private_data_x is: " << derived.Get() << endl << endl << endl;<BR> cout << " After " << endl;<BR> derived.Set(100);<BR> cout << "Base's private_data_x is : " << base.Get() << endl;<BR> cout << "Derived's private_data_x is: " << derived.Get() << endl << endl;<BR> cout << " This time " << endl;<BR> base.Set(200);<BR> cout << "Base's private_data_x is : " << base.Get() << endl;<BR> cout << "Derived's private_data_x is: " << derived.Get() << endl << endl;<BR></BLOCKQUOTE> }<BR> <P><BR><HR> /* Before:<BR> Base's private_data_x is : 0<BR> Derived's private_data_x is: 0<BR> <P> After<BR> Base's private_data_x is : 0<BR> Derived's private_data_x is: 100<BR> <P> This time<BR> Base's private_data_x is : 200<BR> Derived's private_data_x is: 100<BR> <P> Press any key to continue<BR> <A HREF="week2.html">Go Back</A> </BODY> </HTML>