Given the for loop construct: for ( expr1 ; expr2 ; expr3 ) { statement; } Which two statements are true?

Question

Options

• AThis is not the only valid for loop construct: there exits another form of for loop constructor.
• BThe expression expr1 is optional. It initializes the loop and is evaluated once, as the loop begins.
• CWhen expr2 evaluates to false, the loop terminates. It is evaluated only after each iteration through the loop.
• DThe expression expr3 must be present. It is evaluated after each iteration through the loop.

• A
  11% (4)
• B
  84% (31)
• D
  5% (2)

Explanation

B is correct because expr1 is indeed optional - you can omit it (e.g., for (; expr2; expr3)) - and when present, it runs exactly once before the loop begins, making both claims in B accurate. C is correct because expr2 acts as the loop's exit condition: when it evaluates to false, execution exits the loop, and it is re-evaluated after each iteration completes (before the next one starts).

A is wrong because the question treats this as the only valid for construct in the given language context - the enhanced for-each loop (for (Type var : collection)) is a separate construct, not an alternate "for loop constructor" in the same category. D is wrong because expr3 is not required - you can omit it just as you can omit expr1 or expr2; a bare for (;;) is a valid (infinite) loop - so the word "must" makes D false, even though the second half (evaluated after each iteration) is accurate.

Memory tip: Think of the three expressions as I-C-U - Initialize (optional, once), Check (terminates on false, every cycle), Update (optional, every cycle). Only the Check has a terminating effect; the other two are entirely optional.

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