Can someone explain why this php code prints 1 ??

<?php

$n=0;
if ($n<6&&$n>0) {
   echo ++$i."\n";
   ++$n;
}

the value of $n is not > 0 but exactly 0.
Php 7.4 x86

Edited 8 hours ago8 hr by CodeExplorer

17 minutes ago, CodeExplorer said:

Can someone explain why this php code prints 1 ??

<?php

$n=0;
if ($n<6&&$n>0) {
   echo ++$i."\n";
   ++$n;
}

the value of $n is not > 0 but exactly 0.
Php 7.4 x86

Hello Friend,

I Just noticed something about in your snippet. The code prints 1 not because of $n, but because $i was never defined. In PHP, doing ++$i on an undefined variable automatically converts NULL to 1, which is why you get 1 as output.

Edited 8 hours ago8 hr by .hloire

<?php

$n=0;
if ($n<6&&$n>0) {
   echo "Shouldn't print this"."\n";
}

Won't print anything.

    3     0*       ASSIGN                                                   !0, 0
    4     1*       IS_SMALLER                                       ~2      !0, 6
          2*       JMPZ_EX                                          ~2      ~2, ->5
          3*       IS_SMALLER                                       ~3      0, !0
          4*       BOOL                                             ~2      ~3
          5*       JMPZ                                                     ~2, ->7
    5     6*       ECHO                                                     'Shouldn%27t+print+this%0A'
    7     7*       RETURN                                                   1

if ((!0<6)==false)
goto 5*; goto 7*; so will got out of if
else if ((0<!0)==false)
goto 7*; so will got out of if
{
// IF BODY
}
7*:

rewrite:
if ((!0<6)==false||(0<!0)==false)
out of jump
else
{
if body
}

let's reverse:
if ((!0<6)==true&&((0<!0)==true)
if body
else
{
out of jump
}

But now let's try:

if ($n<6||$n>0) {
   echo ++$i."\n";
   ++$n;
}

    4     0*       ASSIGN                                                   !0, 0
    5     1*       IS_SMALLER                                       ~3      !0, 6
          2*       JMPNZ_EX                                         ~3      ~3, ->5
          3*       IS_SMALLER                                       ~4      0, !0
          4*       BOOL                                             ~3      ~4
          5*       JMPZ                                                     ~3, ->10
    6     6*       PRE_INC                                          $5      !1
          7*       CONCAT                                           ~6      $5, '%0A'
          8*       ECHO                                                     ~6
    7     9*       PRE_INC                                                  !0
   15    10*       ECHO                                                     '+'
         11*       RETURN                                                   1

if (!0<6==true)
JMP 5* No JMP 10* // LEAD TO IF BODY
else
if (0<!0==false)
JMP 10* // jump out of if
{
// IF BODY
}
10*:

let's rewrite:
if (!0<6==true)
jump to if body
if (0<!0==false)
jump out of if body
else
jump to if body

if (!0<6||0<!0)
jump to if body
else
jump out of if body

Ok. Everything make sense now.