Access modifiers and array of objects

There are three Access Modifiers:-

1.public

2.private

3.protected

and 4 Access controls:-

1.private

2.public

3.protected

4.default/friendly/no modifier

private:-Accessible with in only same class.

default:-this is the by default access of a variable or function.

default are accessible with in the same package.

protected:-accessible in same package or child class.

protected=default+child class

Child class may be in the same or different package.

Note:-We also need to import the package for using the public and protected members in another package.

Note:-class can be public or default. But can’t be private or protected.

Note:-In java only one class can be public and the name of class must be same otherwise you well get compile time error.

Array of Objects:-

First of create a array by writing

Complex[] c=new Complex[n];

n is the size of array of datatype Complex.

Now  use a loop

for(int i=0;i<n;i++)

{

 c[i]=new Complex();

}

This will create a array of objects.

Note:-we if skip c[i]=new Complex(); then we c[i] is referencing to null(by default). So we get null pointer exception.

Ques:-Write a program to calculate the sum of n complex numbers using array of objects.

Ques:-Write a program to calculate the sum of n rational numbers using array of objects.