[SOLVED] Random .gif images in a test

[scdas]

Hi

I am writing a maths test which makes up "random" questions.  As part of this I wish to choose a random .gif image (eg an equation obtained using the equation editor in MS Word.) from three stored images named in an array: $q6image=array("/q6_1image.gif","/q6_2image.gif","/q6_3image.gif");

  The aim is to pass a random .gif image in this First program to Second program (via use of a form & PHP).  Question 6 is  a question, one of many questions, as part of the test.  Below are relevant snippets of code.  Skipping down to the end of this my basic question is why does the line:

echo "<img src=$q6image[1] >";    works, while the line below doesn't

echo  "<img src=".$q6image[$_SESSION['value_of_q6rn']].">";

      Any hints/suggestions, greatfully received.

David

 

First program:

//HTML interspersed with <? PHP ?>

 

$q6rn=rand(0,2);  //gets a random number in range 0 to 2

$q6image=array("/q6_1image.gif","/q6_2image.gif","/q6_3image.gif");

 

$_SESSION['value_of_q6rn'] = $q6rn;

 

<!-- question 6 //-->

<tr>

                  <td colspan="2" >6. Simplify the expression:  <img src=<? echo $q6image[$q6rn] ?> >

                    <br>

                  </td>

                </tr>

 

Second program:

 

$q6image=array("../q6_1image.gif","../q6_2image.gif","../q6_3image.gif");

 

 

// Below works * * * * * * * * * * * * * * * * * * * * * * * * *

//echo "<img src=$q6image[1] >";

//Below doesn't work; $_SESSION['value_of_q6rn'] appears to have a NULL value

echo  "<img src=".$q6image[$_SESSION['value_of_q6rn']].">";

 

[AndyB]

... because you need to have a line like

 

<?php session_start(); ?>

 

to get sessions started before you can set a session variable.

[scdas]

Thanks for the advice re the 'session_start();' code, but I already had that in both programs.  Any other suggestions?

 

 

... because you need to have a line like

 

<?php session_start(); ?>

 

to get sessions started before you can set a session variable.

[scdas]

FYI

Got it to work - the problem appears to be that the array variable won't take a subscripted varaiable.  Here is my workaround. 

 

$temp=$_SESSION['value_of_q6rn'];

//echo $tab4."<img src=$q6image[$_SESSION['value_of_q6rn']] >"; NB Won't accept variable subscript

echo $tab4."<img src=$q6image[$temp] >";

 

Cheers

David