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funny "for loop"

Lucas Smith
Ranch Hand

Joined: Apr 20, 2009
Posts: 808

Does not compile:

Compiles fine:

I think that compiler wants to prevent us - the first statement is useless - we do not do anything with int - just declaring, but when we add curly braces the situation is different. We have THE SCOPE of an int in which that variable can be used, so compier doesn't give any error.

Am I right?
Correct me if I am wrong.

Henry Wong

Joined: Sep 28, 2004
Posts: 20380

Short answer.... it is simply defined that way. The JLS defines the body of a ForStatement as having a Statement. A LocalVariableDeclaration is *not* one of the options of Statement, hence, illegal for the first case. In the second case, a BlockStatement is an option for Statement, and a BlockStatement is defined to contain LocalVariableDeclarations, hence, legal.


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
subject: funny "for loop"
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