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JavaScript

Posted by Rami Saleh Alsayed
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Rami Saleh Alsayed
Front End Web Development Techdegree Graduate 13,484 Points

Why result is different ?!!

let i;
let text;

i = 0;
do {
  text += i + ' ';
  i += 1;
  } while(i <= 4)

in this case the output will be 0 1 2 3 4.

but why if i write like this : 

i = 0;
do {
  i += 1;
  text += i + ' ';
  } while(i <= 4)

the out put will be '1 2 3 4 5 ' !! why in 'for' loop the i +=1 come first !

1 Answer

Steven Parker
Steven Parker
231,153 Points
Steven Parker
Steven Parker
231,153 Points

It sounds like you nearly answered your own question. In the first example, the number is added to "text" before it is incremented, but in the second example it is added after.

So the first series begins with 0, and the second one begins with 1 (0 + 1).

But both of these are "do...while" loops. A "for" loop works differently in several ways, including performing the test first instead of last.

Rami Saleh Alsayed
.a{fill-rule:evenodd;}techdegree seal-36
Rami Saleh Alsayed
Front End Web Development Techdegree Graduate 13,484 Points

Thank you so much it's clear now !