How can i take user input in dart?

Question

import 'dart:io';
main()
{
  print('What is your name: ');
  String name = stdin.readLineSync();
  print('Your age is = $name');
}

//I'm having this error when i'm taking user input in dart, Error: A value of type 'String?' can't be assigned to a variable of type 'String' because 'String?' is nullable and 'String' isn't.

Solution

I guess you are using null safety. The error occurs because stdin.readLineSync() returns a String? but you assing it on String name. To fix it add a ? or a !, but then make sure it is not null.

String? name = stdin.readLineSync();

String name = stdin.readLineSync()!;

Comments

[quoci]

Did you enabled null safety?

[jamesdlin]

See dart.dev/null-safety/tour

[quoci]

you are welcome! Mark the question as resolved so others will know.

[jamesdlin]

There's a big difference between String? name = ... and String name = ...!. Don't just blindly pick one. The latter will throw an exception if readLineSync() returns null, which can happen it immediately reaches EOF.