Differentiate between required and optional parameters in Dart

In Dart, parameters can be classified as either required or optional. Here's the difference between the two:

Required Parameters

• Required parameters must be provided when calling a function or constructor.
• They are defined without any special syntax, as the default behavior in Dart.
• If a required parameter is missing, the code will not compile[1][2].

Example:

void printDetails(String name, int age) {
  print('Name: $name, Age: $age');
}

Calling the function requires providing both name and age:

printDetails('John', 25);

Optional Parameters

Optional parameters can be further divided into two types: optional positional parameters and optional named parameters.

Optional Positional Parameters

• Enclosed in square brackets [][3].
• Can have a default value specified using =[3].
• If no default value is provided, the parameter's type must be nullable (int? instead of int)[3].

Example:

String say(String from, String msg, [String? device]) {
  var result = '$from says $msg';
  if (device != null) {
    result = '$result with a $device';
  }
  return result;
}

Calling the function with...