Polymorphism

Polymorphism

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Poly means 'many' morphism means 'form' polymorphism means one thing many form.

Compile time polymorphism also known as function overloading

Run time polymorphism also known as function overriding

Function overloading: Function overloading is a compile time polymorphism in which

• The name of the function is same
• Type of parameter or number of parameter must be different 

class addittion

{

int c;

float c1;

void add(int a, int b)

{

c=a+b;

System.out.println(c);

}

void add(int a, int b, int d)

{

c=a+b+d;

System.out.println(c);

}

void add(float a, float b)

{

c1 = a+b;

System.out.println(c1);

}

public static void main(String k[])

{

addition ad = new addition();

ad.add(5,6,7);

ad.add(5,6);

ad,.add(5.6f,6.6f);

}

}

Function overriding: Function overriding is a run time polymorphism and it is possible only through the inheritance.

• Must be inheritance (IS-A relation)
• Name of the functions are same.
• The type of parameter and number of parameter are same.  

class car
{
void show()
{
System.out.println("car class");
}
}
class bmw extends car
{
void show()
{
System.out.println("BMW");
}
public static void main(String k[])
{
bmw bm = new bmw();
bm.show();
car c =  new car();
c.show();
}
}

 Difference between function overloading and function overriding.

Overloading

• In overloading function name are same but parameter type and parameter number must be different.
• It can perform in same and another class.
• It is a compile time polymorphism.
• static method can be overloaded. example: main method of java can be overloaded

Overriding

• The name of the function and type of parameter and number of parameter all are same.
• It can only be perform through the inheritance.
• it is a run time polymorphism.
• static method cannot be override. example: main method of java cannot be override.