a couple of questions

manders76

First-time poster, PHP newbie, will probably be back because this is kinda fun, have a couple of questions:

I get a "Parse error: syntax error, unexpected T_CONSTANT_ENCAPSED_STRING on line 39" for this:

html>
<head>
<title>online calculator</title>
</head>
<body>
<!--building the form here-->
<table border="1">
<tr>
<td>
<form action = "assignment6.php" method = "post">
<input size = "6" name = "number1">
</form>
<form action="assignment6.php" method = "get">
<select name="operation" method ="get">
<option value="add">plus</option>
<option value="subtract">minus</option>
<option value="multiply">times</option>
<option value="divide">divided by</option>
</select>
</form>
<form action ="assignment6.php" method ="get">
<input size = "6" name="number2">
</form>
<input type ="submit" value = "Calculate!">
</td>
</tr>
</table>

<?
$n1=$_GET["number1"];
$n2=$_GET["number2"];

$operation = $_GET["operation"];
if ($operation = "add"){
   print n1+n2;
switch ($operation){
   case "subtract":
      print $n1-$n2";
   case "multiply":
      print $n1*$n2;
   case "divide":
      echo $n1/$n2;
}
}

?>
</body>
</html>

Could use another few sets of eyes; not sure where my error is.

How do I get this to spit out an answer once I put the numbers in? I think I have the foundations of it, but I'm missing a couple of steps and don't know what they are. Hints would be helpful.

Thanks in advance (I hope...).

halojoy

$n1

if ($operation = "add"){
   print n1+n2; 

if ($operation = "add"){
   print $n1+$n2;

   case "subtract":
      print $n1-$n2";

   case "subtract":
      print $n1-$n2;

laserlight

Ah, it is good that you posted in php bbcode tags. Take a look at the syntax highlighting. You would see that there is something strange on this line:

print $n1-$n2";

Basically, you have a stray double quote.

By the way, you probably do not want the fall through behaviour of a switch, so you should use break.

manders76

Okay, errors fixed. However, what I want it to do is spit out a number once I hit "calculate"; what am I missing to do that?

(To see what I mean, look at http://herbie.ischool.utexas.edu/~akmcclen/assignment6.php)

bradgrafelman

Why are the different input elements separated into different FORM tags? You're only going to get the data from one form.

EDIT: Also, one other error:

if ($operation = "add"){

Here, you're using the assignment operator, thus the value of $operation is set to "add". I suspect you wanted to use a comparison operator instead (e.g. a double equal sign). See this page for more info: [man]operators.comparison[/man].

You should also know that the '<?' (and '<?=') short tags have long ago been deprecated. You should always use the full '<?php' tag in all PHP scripts.

manders76

Why are the different input elements separated into different FORM tags? You're only going to get the data from one form.

😕

Here, you're using the assignment operator, thus the value of $operation is set to "add". I suspect you wanted to use a comparison operator instead (e.g. a double equal sign). See this page for more info: operators.comparison.

Even in an if-statement?

You should also know that the '<?' (and '<?=') short tags have long ago been deprecated. You should always use the full '<?php' tag in all PHP scripts.

Duly noted.

cough Would anyone like to help me with this instead of correcting my code? A hint?

What I want it to do is spit out a number once I hit "calculate"; what am I missing to do that?

(To see what I mean, look at http://herbie.ischool.utexas.edu/~ak...ssignment6.php)

bradgrafelman

manders76 wrote:
Even in an if-statement?

Operators have the same meaning no matter where you use them. They don't randomly change functions just because you're using them in an if() statement.

manders76 wrote:
cough Would anyone like to help me with this instead of correcting my code? A hint?

Well until you fix the form problem I mentioned, it's rather impossible to do what you're wanting since the data isn't being submitted at all.

manders76

I just now get the comparison thing. I was thinking something that only makes sense in my head, apparently. 🙂

Fixed the form thing; for some reason I was under the impression that each of the form elements had to be built separately. I was completely unaware of the option of putting them all under one form tag. This is why this is in the Newbie Forum... :p

Now what?

manders76

Whoops, never mind, just figured it out 🙂 Thanks for all your help, y'all.

manders76

Okay, maybe not: For some reason all I can get it to do is add numbers, not switch to the other functions. Updated code here (I know I haven't fixed the <? yet, I know I could probably concatenate the "The answer is" statements; not worried about that at this point):

<html>
<head>
<title>online calculator</title>
</head>
<body>
<!--building the form here-->
<table border="1">
<tr>
<td>
<form action = "assignment6.php" method = "get">
<input size = "6" name = "number1">
<select>
<option value="add">plus</option>
<option value="subtract">minus</option>
<option value="multiply">times</option>
<option value="divide">divided by</option>
</select>
<input size = "6" name="number2">
<input type ="submit" value = "Calculate!">
</form>
</td>
</tr>
</table>

<?
$n1=$_GET["number1"];
$n2=$_GET["number2"];

$operation = $_GET["operation"];
$operation == "add";
   print "The answer is ";
   print $n1+$n2;
switch ($operation){
   case "subtract":
      print "The answer is ";
      print $n1-$n2;
      break;
   case "multiply":
      print "The answer is ";
      print $n1*$n2;
      break;
   case "divide":
      print "The answer is ";
      print $n1/$n2;
      break;
}


?>
</body>
</html>

Test it at herbie.ischool.utexas.edu/~akmcclen/assignment6.php

Pikachu2000

The <select> is unnamed, where it should be <select name="operation">, you have a comparison before the switch which appears to do nothing, and the addition operation isn't included in the switch.