Dart - not specifying a type?

user_16658064 0
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So I was wondering, if I run this code:

incrementionFunc(num1, num2) {
  print(num1+num2);
}

void main() {
  incrementionFunc(2.3,3);
}

I get no issues, and it prints out 5.3. What's the difference between not specifying the type for the variables num1, num2, and writing out var for example (var num1, var num2)?

Thanks in advance!

dart flutter
1 Answers

the type is dynamic if you don't specify it

meaning that this will compile but you'll get a runtime error:

void main() {
  incrementionFunc(2.3, '1');
}

As for var, placing it in method signature is redundant since it's the default as well.

As such, this will compile and won't throw an error:

incrementionFunc(var num1, num2) {
  num1 = 12;
  num2 = 13;
  print(num1+num2);
}


void main() {
  incrementionFunc(2.3, "1");
}

You will get different behavior if you replace var with final:

incrementionFunc(final num1, num2) {
  num1 = 12; // Compilation error: The final variable 'num1' can only be set once.
  num2 = 13;
  print(num1+num2);
}
user_102100690
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