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JavaScript JavaScript Loops, Arrays and Objects Simplify Repetitive Tasks with Loops `do ... while` Loops

Posted by Daniel Morel
Daniel Morel
2,957 Points

while(! correctGuess) ?

I get the whole process of making a true or false flag and making the variable.

I don't get why the ! correctGuess and all the rules implicated to it.. can someone explain?

michaelcodes
michaelcodes
5,604 Points
michaelcodes
michaelcodes
5,604 Points

I don't have much JS experience but in most languages ! means not. So this would be saying while NOT correct guess

3 Answers

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

As michael guessed, the "!" symbol is the logical "NOT" operator. So "while (!correctGuess)" means "keep looping if we still do not have a correct guess". When the value of "correctGuess" is set to "true" inside the loop, the loop stops repeating.

Garrosh HellScream
Garrosh HellScream
7,503 Points
Garrosh HellScream
Garrosh HellScream
7,503 Points

while (!correctGuess) is confusing. Whats wrong with using while (correctGuess == false)? It means the exact same thing right? Matter of preference?

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

Sure, if you find that that easier to read, it is a functional equivalent. But it is not as efficient to execute.

Daniel Morel
Daniel Morel
2,957 Points
Daniel Morel
Daniel Morel
2,957 Points

Want to thank everyone for the help and the correct guidance!.

Matt Brock
Matt Brock
28,330 Points
Matt Brock
Matt Brock
28,330 Points

Yep, michaelcodes is correct. the !, is called the Logical Not Operator (sometimes called a "bang"). In your code, the while loop will run until its condition returns false, i.e. until "NOT correctGuess" is true, or the guess is incorrect. Here's the Mozilla Dev Network page on Logical Operators: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_Operators.