using ! operator

Let's break this down and see it in detail to clear our concept about ! operator:

Code :

var correctGuess = false;

do{
//code
if (randomNumber === parseInt(guess){ correctGuesss = true; }
}while(!correctGuess)

Do-while loop lets you run the body of loop once at least even if the condition turns out to be false.

while(! correctGuess)

is same as

while ( correctGuess == false)

or in other words , keep on repeating the body of do-while loop as long as correctGuess is false.

! operator is same checking for equality of false but it's when you're checking for conditions:

! correctGuess is same as correctGuess == false;

But Dave is right , ! operator switches the value but not in case of while() or if condition,

Let's see this piece of code :

var check = false;
console.log (!check);

What will be the output on console? It will true ! Why ?

Well, !check is same as saying switch the value of check (if it's true then show it false and vice versa).

But in case of conditions of while and if and for loop , it works a bit different.

Finally this code,

var check = false;
check = ! check;
console.log(check);

It will also print value as True, because ! check is not being a part of any while, if or for loop condition in the above code.

I hope it answers your question, Happy Coding :)

• Zain