Lets start by defining what a variable is, a variable is a named space that stores values in memory.

Syntax

A variable must be declared before it is used. Dart uses the var keyword to achieve the same.

var name = 'levis';

All variables in dart store a reference to the value. Uninitialized variables have an initial value of null. This is because Dart considers all values as objects. Look at the example below.

void  main(){
String name;
print (name);
}

output

null

Dynamic keyword

Variables declared without a static type can be referred as dynamic. Variables can be also declared using the dynamic keyword in place of the var keyword. Example

void main() { 
   dynamic y = "levis"; 
   print(y);  
}

Final and const

The final and const keyword are used to declare constants. In Dart, values of a variable declared using the final or const keyword can not be modified. Variables declared using the const keyword are implicitly final

Syntax

Final keyword

final variable_name

Const keyword

const variable_name

Example of final keyword code

void main() { 
   final num1 = 50; 
   print(num1); 
}

Output

50

Example – const keyword

void main() { 
   const pi = 3.14; 
   const area = pi*5*12; 
   print("The output is ${area}"); 
}

The above example declares two constants, pi and area, using the const keyword hence area variable’s value is a compile-time constant.

Output

The output is 188.4

Note : Final and const variables can’t be modified.