Inheritance

//Defines the superclass.
class superclass
 
class subclass
    inherit superclass

//Defines the superclass class.
class superclass
    //Creates a few variables and methods, which will be
    //passed to the subclass.
    integer a = 1, b = 2, c = 3
 
    integer a_value()
        return a
 
    integer b_value()
        return b
 
    integer c_value()
        return c
 
//The subclass class, which inherits from superclass.
class subclass
    //Indicates the class it inherits from.
    inherit superclass
 
    //As these values have been defined before, they are
    //written without a data type, to indicate modification.
    a = 2
    b = 4
    c = 6
 
    //a_value() has been defined before, so it is written
    //without a data type.
    a_value()
        return a * 2
 
    //Defines a new method.
    integer sum_value()
        return a + b + c
 
//A new class, which inherits from subclass. In this case,
//subclass is the parent and superclass is the grandparent,
//though subclass is the superclass to derived_subclass.
class derived_subclass
    //Inherits from subclass.
    inherit subclass
 
    //These all existed for superclass, so it inherits them
    //from subclass.
    a = 4
    b = 8
    c = 12
 
    //Defines a new variable.
    integer d = 16
 
    //Modifies the sum_value() method from subclass.
    sum_value()
        return a + b + c + d

#include <std.dflt.*>
 
//Defines the superclass.
class superclass
    void Output(string s)
        environment.outputln(s)
 
//Defines the subclass.
class subclass
    //Inherits from superclass.
    inherit superclass
 
    //Modifies the Output() method.
    Output(string s, string p)
        if(p)
            environment.outputln("[p]: [s]")
        else
            //Calls the actions of the parent's method,
            //with the appropriate arguments.
            parent.Output(s)