I followed the wiki artichle (http://codeigniter.com/wiki/gchart/revision/5312/) to practice google chart in my CI 2.0. But it doesn't work.
controller file: ci\application\helpers\mytest.php
$this->load->helper( 'gchart' );
$this->load->view('my_test');
view file: ci\application\helpers\my_test.php
$encoded_data = extendedencode(array(0, 1, 2, 3, 4, 5, 6) &maxvalue;);
echo <<< EOS
<img src="
http://chart.apis.google.com/chart?
cht=lc
&chs=250x250
&chd;:e{$encoded}
"
alt="line graph of some example data" />
EOS;
help file: ci\application\helpers\gchart_helper.php
// I do copied all the source code from the wiki url link above.
When I try to charted by CI. It showed error as this, Parse error: syntax error, unexpected ';' in C:\xampp\htdocs\demo\ci\application\views\my_test.php on line 54
Any thing wrong on my operation? I compared the extendedencode() from gchart_helper.php
function extendedencode($data, &$maxvalue='notspecified')
and extendedencode() from my_test.php
$encoded_data = extendedencode(array(0, 1, 2, 3, 4, 5, 6) &maxvalue;);
Then I updated the extendedencode() line to this in my_test.php view file,
$encoded_data = extendedencode(array(0, 1, 2, 3, 4, 5, 6), &maxvalue);
And try again, but still get this error below.
Parse error: syntax error, unexpected ')', expecting T_PAAMAYIM_NEKUDOTAYIM in C:\xampp\htdocs\demo\ci\application\views\my_test.php on line 54
Any help or comments are great appreciated.
[updated]
When I use the formated below,
$encoded_data = extendedencode(array(0, 1, 2, 3, 4, 5, 6) &maxvalue);
showed another four error message.
Events List
A PHP Error was encountered
Severity: Notice
Message: Use of undefined constant maxvalue - assumed 'maxvalue'
Filename: views/my_test.php
Line Number: 54
A PHP Error was encountered
Severity: Warning
Message: max() [function.max]: When only one parameter is given, it must be an array
Filename: helpers/gchart_helper.php
Line Number: 49
A PHP Error was encountered
Severity: Warning
Message: Division by zero
Filename: helpers/gchart_helper.php
Line Number: 55
A PHP Error was encountered
Severity: Notice
Message: Undefined variable: encoded
Filename: views/my_test.php
Line Number: 61
[Updated against Frank's suggestion]
There are still two errors occurred below,
A PHP Error was encountered
Severity: Notice
Message: Undefined offset: 64
Filename: helpers/gchart_helper.php
Line Number: 65 // code line: $ret .= $grid[$x].$grid[$y];
A PHP Error was encountered
Severity: Notice
Message: Undefined variable: encoded
Filename: views/my_test.php
Line Number: 61 // code line: &chd;:e{$encoded}
Alex's answer isn't syntactically correct. Try:
$encoded_data = extendedencode(array(0, 1, 2, 3, 4, 5, 6), $maxvalue);
The & in the function documentation just tells you that your variable will be used by reference. You shouldn't (and in fact cannot) include the & when you call the function. In older versions of PHP, there was a feature called call-time pass by reference, in which you'd use syntax like that, but it's disallowed in recent versions.
Edit:
Regarding one of the additional errors you've listed: as the error says, there's no $encoded var in the code you've shown us. Try replacing &chd;:e{$encoded} with &chd;:e{$encoded_data} -- I'm guessing that might be what you intended.
A sloppy method of silencing the final error would be to replace $ret .= $grid[$x].$grid[$y]; with $ret .= @$grid[$x].@$grid[$y];. Without additional context for the code in play there, it's hard to say what the actual root issue is there.