What is polymorphism explain and example?

Answer 1

Polymorphism is the use of different Types to declare a variable, it is closely related to the inheritance hierarchy. It is used to often hide information from the client concerning how a piece of code works, they should only concern themselves with how to use it.

For instance:

//Declaring lists

//Can declare like this

ArrayList list = new ArrayList();

//or to hide information on how the list is implemented

List list2 = new ArrayList();

//Therefore the user only needs to know the List interface's methods to interact, don't //have to be concerned about the ArrayList implementation.

Some syntax rules for polymorphism:

//You have to Declare using the same or higher level of inheritance than you are //instantiating the Object as

//i.e. Child class is a child of the Parent class (i.e. Child extends Parent)

//therefore, you can

//Declare as a Parent

Parent c1 = new Child(); // Example 1

//Declare as a Child

Child c2= new Child(); //Example 2

//But you cannot declare as a Child and instantiate as a Parent

Child thisIsWrong = new Parent(); //Example 3

A really good check to see if you have the Instantiation right is to say the Instantiating class name(the one after the "=")IS A Declaring class name(the one before the "=") , if the statement makes sense then it is legal. For example, example 1: Child is a Parent? true, legal. example 2: Child is aChild? legal. example 3: Parent is a Child? false, illegal.

Using Polymorphism

Polymorphism hides the child's methods from the user if the variable is declared with the parent, which is useful if you don't want the user messing with the child methods.

As with the top example, first example with the declaration as a Parent c1 cannot use the child methods unless you cast c1 into a child (i.e. ( (Child) c1).cry() ). But in example 2 the Child method could be used since c2 is essentially a Child.

Answer 2

Polymorphism is an object oriented concept which was implemented in C++ first. It is the ability to take more than one form.

Polymorphism is of 2 types:

1.Function overloading

2.Function overriding

1.Function overloading:

Same function used in the

program to perform different operations.. They vary in number of parameters or by the data type of the parameters or by the return type of the function.

For example, lets consider the program for adding numbers.

class A

{

int sum;

void add(int

x, int y) // addition of two numbers

{

sum=x+y;

cout<<"Sum

of 2 nos."<

}

void add(int

x,int

y,int

z)

{

sum=x+y+z;

cout<<"Sum

of 3 nos."<

}

};

void main()

{

A obj;

obj.add(10,20);

obj.add(10,20,30);

}

Here, the function "add()" is overloaded. Addition of 2 and 3 numbers are performed with the same function name..

2.Function overriding:

Same function with same number of parameters used to perform different operations.

for example,

class A

{

void display(int

x)

{

x=x+x;

cout<

}

};

class B : public A

{

void display(int

y)

{

y=y+10;

cout<

}

};

void main()

{

A a;

a.display(10);

B b;

b.display(10);

}

Here, the function "dispay()"

is overridden i.e)

the "display()" function have same structure in both the classes. To call the function in class "A", an object is created for this class and called, for class "B" another object is created and called.

Answer 3

it is a smart material that is usually used for handles, bottle caps, pens etc

Its smart because it congeals at 60 degrees which is safe.

it is often used in schools.