What Is A Variable and How To Define and Use Variables In Programming Languages Like PHP, Python, Java, C#, C/C++, JavaScript, PowerShell, Bash? – POFTUT

# What Is A Variable and How To Define and Use Variables In Programming Languages Like PHP, Python, Java, C#, C/C++, JavaScript, PowerShell, Bash?

Variables are an important part of the programming languages. Variables are used to store information for basic types like name, age, label, address, count, etc. Variables are named accordingly related to the information or data we want to save.

## Variable Types

As there are different data types we generally use variables for specific types. Different programming languages provide very similar data types. Here list of the variable types.

• Integer Variable Type
• Character Variable Type
• String Variable Type
• Boolean Variable Type
• Float Variable Type
• Double Variable Type

### Integer Variable Type

Integer variable type is used to store numeric types which can be used for calculations. We generally use decimal numbers like 5, 12124, -342 as integer variable types. If we do not use 5 for calculation we can store it as a different type named string variable type. Here are some examples of integer variable type.

```12
-24234
1
0
13241235123512
-5```

### Character Variable Type

The character type is very similar to the String variable type where the String variable consists of single or multiple character variables. Some programming languages provide character variable type as string variable type.`a` , `5`,`z` are stored as character variable type. Here are some examples of character variable type.

```"a"
"<"
"b"
"5"
"0"
"?"```

### String Variable Type

A string variable is used to store text data or values. A string can consist of single or multiple characters. String variable types are used like name, address, comments, etc.

```"poftut.com"
"2234234"
"abc"
"Ahmet Ali Baydan"```

### Boolean Variable Type

Programming languages also provides logic operations and logic data types `True` and `False`. Logic variables are named as `boolean` variables. `0` and `1` can be also used for boolean values.

```True
False
1
0```

### Float Variable Type

Float variables are used to store non-decimal numeric values. We can use more precise values with a float data type. Floating types generally consumes more memory or ram.

```1.2342352
0.12124
42342.1
-12124.433```

### Double Variable Type

Float variable type store some floating point numbers. If we need more details and precision we should use double variable types.

```123.23213453242345

-0.24123512351345345345```

## Generic Variable Definition Syntax

Where different programming languages provide different variable definition syntax. We can provide some generic syntax about variable definition in different programming languages.

`TYPE VARIABLE_NAME=VARIABLE_DATA`
• TYPE is the variable type
• VARIABLE_NAME is the name or label of the variable
• VARIABLE_DATA is the data we want to store in the variable

## Define and Use Variables In PHP

### Define Variable In PHP

We can define a PHP variable just prefixing the variable named with the `\$` sign. We can also set the variable value with the `=` sign.

``````//Integer Variable Type
\$age=25;

//String Variable Type
\$name="Ahmet";

//Float Variable Type
\$rate=12.4;``````

### Use Variable In PHP

We can use these different variables in PHP like below. In this example, we will print the variable values to the standard output or screen.

```//Integer Variable Type
echo \$age;

//String Variable Type
echo \$name;

//Float Variable Type
echo \$rate;```

## Define and Use Variables In Python

We can define Python variables easily without using any special sign or type keyword.

### Define Variable In Python

We can define Python variables without a special sign for the variable name. We will also use `=` to assign variable value.

``````//Integer Variable Type
age=25

//String Variable Type
name="Ahmet"

//Float Variable Type
rate=12.4``````

### Use Variable In Python

We can use the Python variable like below.

``````//Integer Variable Type
print(age)

//String Variable Type
print(name)

//Float Variable Type
print(rate)``````

## Define and Use Variables In C/C++

C and C++ programming languages uses the same syntax for variable definition.

### Define Variable In C/C++

In C/C++ we use variable type before specifying the name of the variable.

``````//Integer Variable Type
int age=25;

//String Variable Type
char name[]="Ahmet";

//Float Variable Type
float rate=12.4;``````

### Use Variable In C/C++

While using the variables in C/C++ we should specify the variable name.

``````//Integer Variable Type
printf("%d",&age);

//String Variable Type
printf("%s",&name);

//Float Variable Type
printf("%f",&rate);``````

## Define and Use Variables In Java

Java variables are similar to the C# and C/C++ programming langues.

### Define Variable In Java

We will specify the variable types before the variable names.

``````//Integer Variable Type
int age=25;

//String Variable Type
String name="Ahmet";

//Float Variable Type
float rate=12.4;``````

## Define and Use Variables In C#

C# variables are similar to the Java variables.

### Define Variable In C#

We will specify the variable types before the variable names.

``````//Integer Variable Type
int age=25;

//String Variable Type
string name="Ahmet";

//Float Variable Type
float rate=12.4;``````

## Define and Use Variables In JavaScript

JavaScript is a dynamic and interpreted language where everything is an object.

### Define Variable In JavaScript

We can use `var` keyword before the variable name but its optional which makes the definition readable.

``````//Integer Variable Type
var age=25;

//String Variable Type
var name="Ahmet";

//Float Variable Type
var rate=12.4;``````

## Define and Use Variables In PowerShell

PowerShell is a dynamic language where types are set automatically.

### Define Variable In PowerShell

We will use `\$` sign by prefixing the variable name and set the value.

``````//Integer Variable Type
\$age=25;

//String Variable Type
var name="Ahmet";

//Float Variable Type
var rate=12.4;``````

## Define and Use Variables In Bash

Bash is a shell environment for Linux distributions. It provides some programming features and supports variables.

### Define and Use Variable In Bash

We can create a variable for Bash like below.

``````//Integer Variable Type
age=25

//String Variable Type
name="Ahmet"

//Float Variable Type
rate=12.4``````