Loop Challenge, decrementing a variable

Question

Looking for the proper way to do this. I managed to get the answer, but I don't think it was how I was supposed to do it.

I'm supposed to use a for loop, to decremment var countDown by one each time the loops runs until it equals 0.

var countDown = 10; 

for (let i=0; i < 5; i++)
countDown = countDown-i

console.log(countDown) // output 0;

I understand why my way works. But it doesn't decrement by one. Another way I thought was:

var countDown = 10;

for(i=0; i < 11; i++){
console.log(countDown-i);
}

console.log(countDown) // output 10, 9 , 8, 7, 6, 5, 4, 3, 2, 1, 0, 10

How would I globally change the countDown variable to 0?

Possible duplicate of [JavaScript closure inside loops – simple practical example](https://stackoverflow.com/questions/750486/javascript-closure-inside-loops-simple-practical-example) — Vincent Taing, Jul 03 '18 at 23:44

score 0 · Answer 1 · answered Jan 20 '21 at 09:13

0

let countDown = 10;
for(let i = 0; i < 10; i++){
  countDown--;
}

console.log(countDown); //print 0;

answered Jan 20 '21 at 09:13

Payam

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1

1

Hello and welcome to SO! While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value. Please read the [tour](https://stackoverflow.com/tour), and [How do I write a good answer?](https://stackoverflow.com/help/how-to-answer) – Mhd Alaa Alhaj Jan 20 '21 at 09:29

Keith Nicholas · Answer 2 · 2018-07-03T22:49:57.123

-1

Simple way using a for loop.

    var countDown = 10;
    for(;countDown > 0; countDown--) { 
        console.log(countDown);
    }
    console.log(countDown);

Depending on what the context is, you can put the var in the for loop too like

for(var countDown = 10; countDown > 0; countDown--)

edited Jul 03 '18 at 22:49

answered Jul 03 '18 at 22:42

Keith Nicholas

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"until it equals 0" - this code decrements it to `-1`. – ASDFGerte Jul 03 '18 at 22:47

nixkuroi · Answer 3 · 2018-07-03T23:02:04.943

-1

Just make countdown the variable in your loop and decrement while > -1.

for (var countDown = 10; countDown>0;countDown--)
{
  console.log(countDown);
}
console.log(countDown);

edited Jul 03 '18 at 23:02

answered Jul 03 '18 at 22:50

nixkuroi

2,259
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"until it equals 0" - this code decrements it to `-1`. – ASDFGerte Jul 03 '18 at 22:56
@ASDFGerte No. If you run the snippet, it runs while it's greater than -1, which is 0. Check the output from the snippet. – nixkuroi Jul 03 '18 at 22:57
run your snippet now, I added one more console.log – Keith Nicholas Jul 03 '18 at 22:59
@nixkuroi if you run an extra `console.log(countDown);` _after_ the _for..loop_, you'll see it outputs `-1` – Asons Jul 03 '18 at 22:59
Ah. Fixed based on your comments. – nixkuroi Jul 03 '18 at 23:02

score -1 · Answer 4 · edited Nov 28 '19 at 03:40

let countDown = 10;
// ADD CODE HERE

for (let countDown=10; countDown <=10 && countDown > 0;)
{
    countDown--
}

// Uncomment the below line to check your work 
//console.log(countDown) // -> should print 0;

This will decrement the countDown by 1 from 10 to 0 but the challenge asks for only the zero to be displayed after the code had run.

This will display 0 after the code had run.

To display the countDown from 10 to 0 write the for loop like this:

for (let countDown=10; countDown <=10 && countDown > 0; countDown--);

Loop Challenge, decrementing a variable

4 Answers4