John Davidson

Message:

I have a question about a small piece of code in C to make the same piece of code work in PHP, it has to do with a bit shift and I can't figure out what's wrong.

C:

unsigned u = 3910796769;

u += u << 8;

printf("%u\n",u); 

//Result : 52422369

PHP:

$u = 3910796769;

$u += $u << 8;

printf("%u\n",$u);

//Result : 1005074769633

---

My Answer:
The issue here is with the way bit shifting is handled in C versus PHP. In C, the << operator is used for left shifting bits, while in PHP, the << operator is used for concatenation.

To achieve the same result in PHP as in the C code provided, you can use the bitwise shift operators >> and << for left and right shifting respectively.

Here is the corrected PHP code:

php
$u = 3910796769;
$u += $u << 8;
printf("%u\n", $u);
//Result : 52422369


This should give you the same result as the C code.