Data types are a quite important topic in the programming world. It's a list of types of information which can be used to store/evaluate/process. It can be generally classified into Primitives, Composites and Custom defined. A thread on it. {1/8}

Data Types

Primitive data types are types of data which are pre-defined in the computer/programming language. {2/8}

Primitive data types

Primitive data types generally include,<ul><li dir = "auto">Integers (Real numbers)</li><li dir = "auto">Floats and Doubles (with fractional values)</li><li dir = "auto">Character (A single character in the character set)</li><li dir = "auto">String (Group of characters)</li><li dir = "auto">Boolean(either true or false).</li></ul> {3/8}

Composite data types are types of data which are derived from one or more primitive data types. {4/8}

Composite data types

Composite data types include,<ul><li dir = "auto">Arrays (group of primitive data types under a single identifier)</li><li dir = "auto">Unions</li><li dir = "auto">Sets</li><li dir = "auto">Lists, etc.,</li></ul> {5/8}

Custom defined data types are actually defined by the programmer through code by extending/including other data types. {6/8}

Custom defined data types

They can create a structure which fits their needs. Example, create a data type which holds three values which are related to a specific thing (like an object or map). {7/8}

Custom defined types are much more like Map or Object, but the main difference is Custom defined types are derived from maps, and can be used totally as a new data type. {8/8}

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Variables and Constants are mostly misunderstood in programming. Most of the time, most of the people read bad definitions on Constants. A thread on this.

Variables vs Constants

First of all, we need to understand the usage of both variables and constants. Variables are used to store values which can be changed in run time whereas constant cannot be changed. {1/9}

But some of the websites/people explain these two in the wrong way. Mostly the definition for constant would be "A constant is a variable that can't be changed in the program". {2/9}

It totally makes no sense. This statement states that a CONSTANT is a VARIABLE but it's value can't be changed. If CONSTANT is a VARIABLE then the value can be changed. A total collapse in the meaning. {3/9}

So, both "Variable" and "Constant" come under a concept called "Identifiers". As the name suggests, identifiers help us to identify a value which is stored in the memory with the help of a name. It's like a box which contains some values/information with a label attached. {4/9}

Say if you wanna store a number "42" in your program/code, you can assign it to an identifier. So that you can use it later in your program. {5/9}

If a value stored in an identifier which can be changed in the run time, it is called a "Variable". If it cannot be changed it is called a "Constant". {6/9}

Values stored in memory can't be accessed without knowing the address. Since we can't remember addresses, we need some kind of label which points to that address. Something like a contact number saved in the phone. We can’t remember phone numbers, but we can remember names. {8/9}

Also Also identifiers can be function names, type names, class names, labels, etc.,can be function names, type names, class names, labels, etc., {9/9}

Data Types

Variables vs Constants

DJ Hemath