What is a variable in Dart?
variables are used to store the value at the memory location. It contains a namespace referring to memory location. Declaration
Variables can be declared in multiple ways
You can use using var keyword or directly use the type without the var keyword
Syntax:
type variableName;
var variable=value;
The first one is a type of variable that must be declared with a variable name. Type can be primitive or custom types declared in Dart.
Syntax: Single variable declaration syntax
type variableName;
Multiple variables can be declared with a separator comma(,)
type variableName;
type is a datatype of a variable value to store it.
It can be built type or custom type
The following are built primitive types.
- number types: Numerical values such as num, int, double
- string : String of values
- bool : a true or false values
- dynamic :
- list :
- map:
- set:
Here is an example of declaring variables in multiple ways
void main() {
// declare using var
var str = "welcome";
//declare using type
String str2 = "hello";
}
the first variable is declared and initialized with stringvalue. The Dart compiler checks the right-hand value type, here is a string type, and the variable has inferred this type as a string type.
The second way, declare a variable with String type and assign it a value.
Default value for the variable
variables declared without initialization have a default value of null.
Variable scopes
Each Variable declared in dart has scope and scope is lifetime based on the place of declaration.
There are two types of variable scopes.
- Global Variable
- Local Variable