Pascal: Identifiers

SELF TEST 1. Which of the following are valid Pascal identifiers?

	 birthday     Too_hot?        First_Initial
	 grade        1stprogram      down.to.earth
	 see you      OldName         case

Valid identifiers begin with a letter, then followed by any digit, letter or the underscore character ( _ ). Looking at the list above, the valid identifiers are

	birthday
	First_Initial
	grade
	OldName

Sample Identifier	Reason why it is invalid
Too_hot?	?
1stprogram	begins with a digit
down.to.earth	.
see you	illegal space
case	reserved keyword