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What is a var type in Dart?

Maria Elijah

Dart var type

In Dart, when a variable is declared as a var type, it can hold any value such as int and float.

The value of a var variable can not change within the program once it is initialized at declaration.

Syntax


var variable_name

Example 1

The following code shows how to implement the var type in Dart.

void main() {
  var a;       // declaring a variable of type var
  a = 40;      // initializing variable a
  print(a);

  a = "Dart";  // reassigning string value to `a`
  print(a);

  a = 10.4;    // reassigning float value to `a`
  print(a);
}
Using type var to create variables in Dart

Explanation

  • Line 1–11: We create the main() function. Within the main(), we have the following:

    • Line 2: A variable named a of var type.

    • Line 3: We assign an integer value to it.

    • Line 4: We print the value of a.

    • Line 6: We reassign a string value to it.

    • Line 7: We print the value of a.

    • Line 9: We reassign a float value to it.

    • Line 10: We print the value of a.

Example 2

Let’s try initializing at the point of declaring the variable and then reassigning a value to it.


Note: The following code will throw an error.

void main() {
  var a = 40;
  print(a);

  a = "Dart";
  print(a); // Error: A value of type 'String' can't be assigned to a variable of type 'int'
}

Explanation

If we initialize a variable of type var at the point of declaration, we can’t reassign a value to it.

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