CODEWITHSUNDEEP
javascript
Kamil Kowalczuk-Fijałkowski
Kamil Kowalczuk-Fijałkowski

Reputation: 13

Reversing loop javascript

I have a problem with my exercise. I have to draw something like this: https://screenshots.firefox.com/3qaHB7dcr3n610hi/jsbin.com

And this is my code

  var empty = "";
for(var i=0; i < 5; i++) {
  empty += "*";
  console.log(empty)
}

but with this code I can only make this:

*  
**
***
****
*****

I have no idea how to reverse this loop to start it from top from 5 stars, i tried something like this:

var empty = "";
for (i = 5; i <= 0;i--) {
  empty+="*";
  console.log(empty);
}

But doesn't work. Anybody know how to do this? I will be grateful :)

Upvotes: 1

Views: 59

Answers (4)

theriddle2
theriddle2

Reputation: 418

Just in case you need a nested for loop. (As some exercises sometimes do) 

var k = 0;
for(var i = 1; i < 12; i++){   
    var stx = "";
    for(var j = k; j < i; j++){
        stx += "*";
    }
    if(i > 5) k += 2
    if(i == 6) continue
    console.log(stx);
}

Upvotes: 0

Ele
Ele

Reputation: 33726

  • Your approach builds the first part.
  • The second part can be accomplished using the function slice in descending direction.

var empty = "";
var i = 0;

// Build the first part
for (; i < 5; i++) {
  empty += "*";
  console.log(empty)
}

// Here i = 5, so this is the initialization for the following loop.
// Loop in descending direction using the function slice.
for (; i > 0; i--) {  
  console.log(empty.slice(0, i))
}
.as-console-wrapper { max-height: 100% !important; top: 0; }

Upvotes: 2

Andy
Andy

Reputation: 63524

Instead of a for/loop you could use a while loop to change the direction:

let stars = 0;
let count = 0;
while (count < 9) {
  if (count < 5) stars++;
  if (count >= 5) stars--;
  const line = Array(stars).fill('*').join('');
  console.log(line);
  count++;
}

Upvotes: 0

yBrodsky
yBrodsky

Reputation: 5041

Your condition was wrong. Check this.

for(let i = 1; i <= 5; i++) {
  console.log('\"' + '*'.repeat(i) + '\"');
}
for(let i = 5; i > 0; i--) {
  console.log('\"' + '*'.repeat(i) + '\"');
}

Upvotes: 1

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