Difference between Overriding and Overloading
Overriding is the example of run-time polymorphism and
Overloading is the example of compile-time polymorphism.
Overriding
■The return type must exactly match that of the overridden method.
■The access level must not be more restrictive than that of the overridden method.
■The access level can be less restrictive than that of the overridden method.
■The overriding method must not throw new or broader checked exceptions than those declared by the overridden method.
■The overriding method can throw narrower or fewer exceptions. Just because an overridden method “takes risks” doesn’t mean that the overriding subclass’ exception takes the same risks. Bottom line: An overriding method doesn’t have to declare any exceptions that it will never throw, regardless of what the overridden method declares.
■You cannot override a method marked final.
■If a method can’t be inherited, you cannot override it.
Overloaded method
■Overloaded methods must change the argument list.
■Overloaded methods can change the return type.
■Overloaded methods can change the access modifier.
■Overloaded methods can declare new or broader checked exceptions.
■A method can be overloaded in the same class or in a subclass.
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Comma separated values in SQL Server
12 years ago
This is a great blog.....
ReplyDeleteI wish I was doing .NET..i would have learnt so much....I can still learn a lot from it though....
Overloading
ReplyDeletedeals with multiple methods in the same class with the same name but different signatures.
class student
{
public string GetName(int id){...}
public string GetName(string ssn){...}
}
Overriding
deals with two methods, one in a parent class and one in a child class that have the same signature.
Class ParentClass{
public string GetName(int id, stringmatch){.}
}
Class ChildClass inherits ParentClass{
public string GetName(stringmatch, int id){.}
}
"access level can be less restrictive than that of the overridden method."
ReplyDeleteThe above statement is wrong because it won't compile when we try to change access specifier weather it is less restrictive.
Check It.
When overriding, you change the method behavior for a derived class.
ReplyDeletee.g Clas A
{
Virtual void hi(int a)
{
}
}
Class B:A
{
public overrid void hi(int a)
{
}
}
Overloading simply involves having a method with the same name within the class.
Example for Over loading
Class A
{
class a()
{
}
class a(int a)
{
}
}