Difference between revisions of "Abstract"
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if all the members are abstract class can be defined as [[interface]] | if all the members are abstract class can be defined as [[interface]] | ||
| + | |||
| + | <pre class="brush:csharp;"> | ||
| + | public abstract class Shape | ||
| + | { | ||
| + | public abstract void Draw(); | ||
| + | } | ||
| + | </pre> | ||
| + | |||
| + | Draw method cannot have a method body, | ||
| + | |||
| + | Derived class must implement all abstract members in the base abstract class | ||
| + | |||
| + | Abstract classes cannot be instantiated | ||
| + | |||
| + | === Why to use Abstract ? === | ||
| + | When you want to provide some common behaviour, while forcing other developers to follow your design | ||
| + | |||
| + | === Virtual vs Abstract === | ||
| + | Virtual can be overridden but not a must and it can have a body. | ||
| + | Abstract must be overridden in derived classes and cannot have a body. | ||
| + | |||
| + | === Interface vs Abstract === | ||
| + | in Abstract classes there can be implementations | ||
| + | |||
| + | --------------- | ||
| + | Related Subjects : [[interface]], [[Polymorphism]], [[Sealed Modifier]] | ||
Latest revision as of 10:39, 13 June 2017
Once you define the name but not implement the body and all child classes should implement their own bodies under defined name it's called abstract.
if you set a method as abstract in a class, you have to define class itself as abstract
if all the members are abstract class can be defined as interface
public abstract class Shape
{
public abstract void Draw();
}
Draw method cannot have a method body,
Derived class must implement all abstract members in the base abstract class
Abstract classes cannot be instantiated
Why to use Abstract ?
When you want to provide some common behaviour, while forcing other developers to follow your design
Virtual vs Abstract
Virtual can be overridden but not a must and it can have a body. Abstract must be overridden in derived classes and cannot have a body.
Interface vs Abstract
in Abstract classes there can be implementations
Related Subjects : interface, Polymorphism, Sealed Modifier
