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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops Review while loops, do...while loops, and Loop Conditions

Posted by Joseph Chauvin
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Joseph Chauvin
Full Stack JavaScript Techdegree Student 12,029 Points

Why would the while loop run the code if the condition is 'false'? I thought that the answer would be only 'Goodbye'?

while (false) {
    console.log('Hello');
}

console.log('Goodbye');```

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

You are correct. Since the condition for the while loop is false, the loop never runs and 'Hello' never prints. But the second console.log does run because it's outside the loop.

Perhaps a stray mouse click caused a different answer to be selected? I've done that once or twice.

Joseph Chauvin
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Joseph Chauvin
Full Stack JavaScript Techdegree Student 12,029 Points

The answer to the question is actually Hello and Goodbye, and the explanation is: "Even though the condition is false, a do..while loop always run at least once."

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

There are two similar questions. The code shown above is from the question on the plain "while" and the answer is just "Goodbye" for the reasons I shared.

There's also a question about a "do...while" that has different code and a different answer. Note that the quiz questions are randomized and you may not get both of them in the same quiz session.

Joseph Chauvin
.a{fill-rule:evenodd;}techdegree
Joseph Chauvin
Full Stack JavaScript Techdegree Student 12,029 Points

It seems that both of those questions you mentioned have the wrong answers to them on the quiz

Joseph Chauvin
.a{fill-rule:evenodd;}techdegree
Joseph Chauvin
Full Stack JavaScript Techdegree Student 12,029 Points

nvm, I think it was bugged or something because now it has the right answers, thank you so much for your help