Variable constants and data types

What is DATA?

Data is the representation of anything.

 so it can be either constant or variables.

So from the basic mathematical definition:

Constant: Entity whose value can not be changed.
Variable: Entity whose value can be changed.

consider we have an equation:

 (x-5)(x+5) = 0

then the value of x will be -5 and 5.

You can notice that value of x is changing. so it is called variable and the value 5 or -5 is constant.

we will mainly focus on variable.

so in programming terms, variables are defined as:

Variables are just a placeholder.

There are 2 types of Data:

1. primitive
2. Non primitive

 Primitive types are system defined data types. They are:

1. int
2. short
3. long
4. byte
5. float
6. double
7. boolean
8. char

First 4 of them are used for round number integers.

5th and 6th one are used for decimal number representation

7th is used as condition- either true or false

8th is used for alphabets representation.

Each data type has a default size and range.

Now let's learn its implementation

The non-primitive data types are referred as user defined data types. Example:

1. String
2. Array
3. objects ..etc

we will learn non-primitive data types in coming posts.