Why output of this code is 6? It is supposed to be 5

Question

https://code.sololearn.com/wwZcqzjG76nI/?ref=app

Answer 1

Its because after the sum will be greater than 10 the value of variable i at that time will be 5 and then the i will get incremented by 1, so it's value will become 6. Then the condition is checked and it is evaluated to be false. So the final value of variable i will be 6.
You can check the code for more understanding : https://code.sololearn.com/wG24Qaz3hO05/#php

Hope this helps !!!

Answer 2

Денис Лапшин
First initialization is done once. Then the condition is checked, then the set of code inside for loop is executed and then the value of variable in updated.
You can get the proper explanation from the below website :
https://www.elated.com/php-for-loops/

Answer 3

It's because you're starting $i at 1.

Here's the loop step-by-step:

$sum = 0;
$arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
for ($i = 1, $a = 0; $sum <= 10; $i++, $a++)
LOOP 1: $sum += $arr[0] = 0+1 = 1, $i + 1 = 2
LOOP 2: $sum += $arr[1] = 1+2 = 3, $i + 1 = 3
LOOP 3: $sum += $arr[2] = 3+3 = 6, $i + 1 = 4
LOOP 4: $sum += $arr[3] = 6+4 = 10, $i + 1 = 5
LOOP 5: $sum += $arr[4] = 10+5 = 15, $i + 1 = 6 - conditions satisfied

Change i$i to 0 and it should work.

Answer 4

Thanks Keval. I thought firstly condition should be checked and then incremented/decremented or something else.

Answer 5

Thanks a lot, Keval