Question:

“The methods defined in the parent class will always override the methods defined in the base class”. What does this statement means?

Answer:

The above statement is a concept of Polymorphism in Perl. To clarify the statement, let’s take an example:

[perl]
package X;
 
sub foo
 
{
 
print("Inside X::foo\n");
 
}
 
package Z;
 
@ISA = (X);
 
sub foo
 
{
 
print("Inside Z::foo\n");
 
}
 
package main;
 
Z->foo();
[/perl]

This program displays:

Inside Z::foo

– In the above example, the foo() method defined in class Z class overrides the inheritance from class X. Polymorphism is mainly used to add or extend the functionality of an existing class without reprogramming the whole class.


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