How is this operator not working in this code?

Question

Code:

var i = 0, finished = false;
    while( (i < acentos.length) && !finished){

Question:

I have a variable bool receiving false, and in my while I am denying her.

If I’m denying a false variable, it flips true, correct?

There I am saying, while i is smaller than vector size E !finished for true, continue?

or

While i is smaller than vector size E !finished for false continue?

when I put a variable bool within a while, it ignores the value that was given to it? And defines how true?.

Complete code below:

  var i = 0, finished = false; // <-- *IMPORTANTE

        while( (i < acentos.length) && !finished){ // <-- *IMPORTANTE
            if (acentos[i] && acentos[i+1] && acentos[i+2]) {
                selSeat = i;

//Codigo..

                var accept = confirm("Reserva da cadeira "+ (i + 1) +" ~ "+(i + 3)+" está disponível, aceitar?.");

                if (accept) {

                    finished = true; // <-- *IMPORTANTE
                }else{
//Codigo..
                }
            }
            i++;
        }

Man while this way in the beginning

while(false && true)

when I accept the "accents" and finished receives true, then my denial operator denies him, so he gets like false, woe mine while gets like this

while( false && false)

as the two conditions are equal he leaves the loop? I may be traveling, but I’m trying to think how logic works.

Answer 1

if I’m denying a false variable, it flips true correct?

No, you are reversing the value contained in the variable, you do not change the variable.

There I am saying, while i is smaller than the vector size E ! finished for true continue?

That, but I would read "as long as i is smaller than the size of vector E is not finished". Or better yet, "as long as i is smaller than the size of vector E is not finished", you have to decide whether it is English or Portuguese.

While i is smaller than vector size E !finished for false continue?

No, this reading is wrong. You can only execute if everything is true. So you cannot analyze how false.

when I put a variable bool within a while, it ignores the value that was given to it? and defines how true?.

This doesn’t make much sense. Nothing is ignored. "Put" is a very ambiguous term. The line finished = true; is assigning true for the variable, probably changing its value, at least as you can see in this code. And this will have consequence in the condition.

my while this so at the beginning while(false && true)

I don’t know, but I believe they’re both true

Oh my while gets like this while( false && false)

This is more difficult to analyze just with this excerpt. But it is to stay true and false, which will close the loop.

as the two conditions are equal he leaves the loop?

No, he leaves when one of his is false, so that the previous statement is wrong, if one of them is false right off the bat or enters the loop the first time.

The && requires that both the right and the left operating be true to give true, according to the truth table.

true && true = true
true && false = false
false && false = false
false && true = false

All code can be better written. Even you don’t need this variable of flag finished.

for (var i = 0; i < acentos.length; i++) {
    if (acentos[i] && acentos[i + 1] && acentos[i + 2]) {
        selSeat = i; //tenho medo desta variável solta
        //Codigo..
        if (confirm("Reserva da cadeira " + (i + 1) + " ~ " + (i + 3) + " está disponível, aceitar?.")) {
            break;
        } else {
            //Codigo..
        }
    }
}

I put in the Github for future reference.

Answer 2

The ! will always deny the expression that comes forward, so:

finished = true;
//!finished = false
finished = false;
//!finished = true;

Answer 3

Two denials are transformed into one statement. ex: Not false -> true not 2 != 2-> not (false) -> true (two is equal to two, then returns a false value). Thus, there in while, since &&(and) is used, the finished value has to be false to fall into the internal code.

Answer 4

I have a bool variable receiving false, and in my while I am denying it. The question is this, if I am denying a false variable, it turns true correct?

when you use ! you reverse the value of it, if it was true it turns false and if it was false it turns true.

There I am saying, as long as I am smaller than the size of vector E ! finished for true continue? or While i is smaller than the size of vector E ! finished for false continue?

You’re saying as long as I’m smaller than the size of the vetro and finished nay is true continues.

when I put a bool variable inside a while, it ignores the value that was given to it? and defines it as true?

Not.

Let me get this straight.. My while is so at the beginning while(false && true)

when I accept the "accents" and finished gets true, then my negation operator denies it, then it gets as false, then my while gets so while( false && false)

as the two conditions are equal he leaves the loop? I may be traveling, but.. I’m trying to think how logic works.

false and true equals false.
If you want it to run if any one is true use or:
false or true equals true.