why can't it be println("todo.count") but println(todo.count) only?

Tu,

Quotes are used to String arguments. Since println() is not printing a String, it does not need quotes. If you wanted to do:

println("Tom")

Then you would place the quotes but you are calling the .count method so quotes are unnecessary. I am new to this myself so I hope that makes sense :P

If you put it inside the quotation marks it will read it as a string while if you dont put it inside the marks then it will read it as a variable. For example if i say int four = 4; and say println("four"); it will print out "four." Meanwhile if I say println(four); it will print out "4" because since I didnt put it in quotation marks and it will look for the variable fourand print out its value which is "4".

thank you for your answers ! i've think i get it now! ^^