[SOLVED] Average of 3 numeric form inputs, with output of a GRADE average

suttercain · March 10, 2007

Hello,

I am trying to have the user enter 3 numeric values in a form. After it is submitted, I want the out put to show their grade average.

Here is my code

HTML:

<body>
<form action="lab_1b.php" method="post"> 
What was your first score?<br>
<input type="text" name="grade1" size=3 /><p></p>

What was your second score?<br>
<input type="text" name="grade2" size=3 /><p></p>

What was your third score?<br>
<input type="text" name="grade3" size=3 /><p></p>
<input type="submit" name="grades" value="Submit" />
</form>

</body>

PHP side

<?php
extract ($_REQUEST);

if ($grade1 + $grade2 + $grade3 / 3  >= 90) {
print "You got an A!";
}

elseif ($grade1 + $grade2 + $grade3 / 3   >= 80 or <=89) {
print "You got a B!";
}

elseif ($grade1 + $grade2 + $grade3 / 3   >= 70 or <=79) {
print "You got a C!";
}

elseif ($grade1 + $grade2 + $grade3 / 3   >= 60 or <=69) {
print "You got a D!";
}

else {
print "You got a F!";
}
?>

I am getting this error:

Parse error: parse error, unexpected T_IS_SMALLER_OR_EQUAL in D:\wamp\www\PHP Tutorials\By Example\examples\chapter7_examples\lab_1b.php on line 16

papaface · March 10, 2007

Should be:

<?php
extract ($_REQUEST);

$total = $grade1 + $grade2 + $grade3 / 3;

if ($total >= 90) {
print "You got an A!";
}

elseif ($total  >= 80 || $total <=89) {
print "You got a B!";
}

elseif ($total  >= 70 || $total <=79) {
print "You got a C!";
}

elseif ($total  >= 60 || $$total  <=69) {
print "You got a D!";
}

else {
print "You got a F!";
}
?>

papaface · March 10, 2007

Although Im pretty sure you should be using AND (&&) in those instead of OR (||)

Also if you are using register_globals you shouldnt.

suttercain · March 10, 2007

Hi Papaface,

I tried your code and I see what you're doing. But now, no matter which numbers I enter I get a "Uou got a B!"

papaface · March 10, 2007

Try:

<?php
extract ($_REQUEST);

$total = $grade1 + $grade2 + $grade3 / 3;

if ($total >= 90) {
print "You got an A!";
}

elseif ($total  >= 80 && $total <=89) {
print "You got a B!";
}

elseif ($total  >= 70 && $total <=79) {
print "You got a C!";
}

elseif ($total  >= 60 && $$total  <=69) {
print "You got a D!";
}

else {
print "You got a F!";
}
?>

suttercain · March 10, 2007

Yeah, the "math" is all messed up. If I enter 100, 60, 60 it outputs A when it should be C (73.333)

chronister · March 10, 2007

Tested and working properly.

<?php
if(!isset($_POST['grades'])){
?>
<form action="<?=$_POST['PHP_SELF'] ?>" method="post"> 
What was your first score?<br>
<input type="text" name="grade1" size=3 /><p></p>

What was your second score?<br>
<input type="text" name="grade2" size=3 /><p></p>

What was your third score?<br>
<input type="text" name="grade3" size=3 /><p></p>
<input type="submit" name="grades" value="Submit" />
</form>

<?
}else{
$grade1=$_POST['grade1'];
$grade2=$_POST['grade2'];
$grade3=$_POST['grade3'];

$total=($grade1 + $grade2 + $grade3) / 3; // set all math here so you only have to do it 1 time

echo 'Your average is '. sprintf("%.2f",$total) .'% <br><br>'; // used sprintf to cut off at 2 decimal places

if ($total  >= 90) {
print "You got an A!";
}

elseif ($total >= 80 && $total <= 89) { // changed the or to &&
print "You got a B!";
}

elseif ($total   >= 70 && $total <=79) { // changed the or to &&
print "You got a C!";
}

elseif ($total   >= 60 && $total <=69) { // changed the or to &&
print "You got a D!";
}

else {
print "You got a F!";
}



}
?>

I tested this and it works. You must specify the && because you want the condition to return true if it is greater than X AND less than X. With the || (or clause) it was giving an A for a 60%

I moved the processing to the same page as the form so I could make it work, if you need to just grab everything in between the else { } and put it in your processing page.

Hope this helps.

suttercain · March 10, 2007

Chronic, you're the man. You got me up and going. Thanks.

Shannon

chronister · March 10, 2007

hehe... chronic

My old highschool nickname has come back to haunt me

suttercain · March 10, 2007

I figured as much

suttercain · March 10, 2007

Whoa... check this out:

Your average is 79.67%

You got a F!

but

Your average is 79.00%

You got a C!

chronister · March 11, 2007

what 3 numbers did you use to get that?

It is because of the structure of the if else statement.

elseif ($total   >= 70 && $total <=79) {
print "You got a C!";
}

79.67 is greater than 70 but not less than 79. Try this. I don't remember the grading scales exactly, but if I remember correctly, 79.99% is still in the C range... like a C+

<?php
if(!isset($_POST['grades'])){
?>
<form action="<?=$_POST['PHP_SELF'] ?>" method="post"> 
What was your first score?<br>
<input type="text" name="grade1" size=3 /><p></p>

What was your second score?<br>
<input type="text" name="grade2" size=3 /><p></p>

What was your third score?<br>
<input type="text" name="grade3" size=3 /><p></p>
<input type="submit" name="grades" value="Submit" />
</form>

<?
}else{
$grade1=$_POST['grade1'];
$grade2=$_POST['grade2'];
$grade3=$_POST['grade3'];

$total=($grade1 + $grade2 + $grade3) / 3;

echo 'Your average is '. sprintf("%.2f",$total) .'% <br>';

if ($total  >= 90) {
print "You got an A!";
}

elseif ($total >= 80 && $total <= 89.99) {
print "You got a B!";
}

elseif ($total   >= 70 && $total <=79.99) {
print "You got a C!";
}

elseif ($total   >= 60 && $total <=69.99) {
print "You got a D!";
}

elseif($total < 60){
print "You got a F!";
}
else { // this is there just to account for anything that is not covered in the above statements.
print "Score was out of range, need to adjust code to account for this percentage";

}
}
?>

suttercain · March 11, 2007

I changed the numbers to floating points and that fixed it. Another question I have is how do I set it so that the user must enter a number.

I know is_numeric() is the right path, I just don't know how to use it.

<?php
if(!isset($_POST['grades'])){
}else{
$grade1=$_POST['grade1'];
$grade2=$_POST['grade2'];
$grade3=$_POST['grade3'];

$total=($grade1 + $grade2 + $grade3) / 3; // set all math here so you only have to do it 1 time

echo 'Your average is '. sprintf("%.2f",$total) .'% <br>'; // used sprintf to cut off at 2 decimal places
if ($total  >= 90) {
print "<h1>You got an A!</h1>";
}
elseif ($total >= 80 && $total <= 89.9999) { // changed the or to &&
print "You got a B!";
}
elseif ($total >= 70 && $total <=79.9999) { // changed the or to &&
print "You got a C!";
}
elseif ($total   >= 60 && $total <=69.9999) { // changed the or to &&
print "You got a D!";
}
else {
print "You got a F!";
}
}
?>

I want to make it so the user has to enter a number, and cannot pass a character.

chronister · March 11, 2007

I placed the numeric check part right in the top as you want to ensure all values are indeed numeric before processing. So the statement reads, if all 3 items are numeric, then process (scroll to bottom of code now.)

<?php
if(!isset($_POST['grades'])){
}else{

if(is_numeric($_POST['grade1']) && is_numeric($_POST['grade2']) && is_numeric($_POST['grade3']) ){


$grade1=$_POST['grade1'];
$grade2=$_POST['grade2'];
$grade3=$_POST['grade3'];

$total=($grade1 + $grade2 + $grade3) / 3; // set all math here so you only have to do it 1 time

echo 'Your average is '. sprintf("%.2f",$total) .'% <br>'; // used sprintf to cut off at 2 decimal places
if ($total  >= 90) {
print "<h1>You got an A!</h1>";
}
elseif ($total >= 80 && $total <= 89.9999) { // changed the or to &&
print "You got a B!";
}
elseif ($total >= 70 && $total <=79.9999) { // changed the or to &&
print "You got a C!";
}
elseif ($total   >= 60 && $total <=69.9999) { // changed the or to &&
print "You got a D!";
}
else {
print "You got a F!";
}


}else{
echo " All Entries Must Be Numeric";
}
}
?>

else at least one entry was not numeric, so print error message.

Nate

suttercain · March 11, 2007

Thank you sir. That worked.

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[SOLVED] Average of 3 numeric form inputs, with output of a GRADE average

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