How does php know what's going on in this small script?

kabetz

I'm obviously an out and out beginner, however before I start thanks for having me on your forum.

I'm just starting out with php and I've been following the lessons on Code Academy. In one section with While Loops they do a small script of tossing a coin and the coin has to land 3 times on heads for the script to stop.

I've attached the script.

What I don't understand is how php knows that in the $flip=rand(0,1) that 1 is heads and 0 is tails.

Also, in the if statement it just say if($flip).

Why do I not have to write if($flip=1) so that it identifies 1 from the rand as being heads?

Thanks Al.[ATTACH]5191[/ATTACH]

heads.png

cretaceous

Welcome to php builder... I'm not going to download an aattchment but..

$flip=rand(0,1) ;
this makes $flip equal to either 0 or 1 randomly
[note : if it was $flip=rand(0,9) you would get 0 to 9 randomly]

When you do

if($flip=1) ...
you are actually assigning the value of 1 to $flip -the same as
$flip=1 ;

To make an equality comparison you need to do:
if($flip==1) ...

When you do
if($flip)..
it's seeing if $flip is 'true'
It's true for any value of 1 or more - it's 'false' for a value of '0'

HTH

kabetz

cretaceous;11046171 wrote:
Welcome to php builder... I'm not going to download an aattchment but..

$flip=rand(0,1) ;
this makes $flip equal to either 0 or 1 randomly
[note : if it was $flip=rand(0,9) you would get 0 to 9 randomly]

When you do

if($flip=1) ...
you are actually assigning the value of 1 to $flip -the same as
$flip=1 ;

To make an equality comparison you need to do:
if($flip==1) ...

When you do
if($flip)..
it's seeing if $flip is 'true'
It's true for any value of 1 or more - it's 'false' for a value of '0'

HTH

Ah! So zero is false and 1 is true. How simple.

thanks.
Al.

PS: My question is answered this thread can be closed.

NogDog

There is a "mark thread resolved" option under the "Thread tools" drop-down at the top of the first post on the page. 🙂

johanafm

kabetz;11046173 wrote:
Ah! So zero is false and 1 is true. How simple.

To be more precise, 0 is false and non-zero is true.

If you leave the numeric realm, both the empty string "" and null evaluates to false.