[RESOLVED] Calculating sums in a range of numbers

Hootnholler

Hi all,

I hope I describe this correctly... I need to calculate the sum of a range of numbers from user input and give an answer. This is actually an assignment that I need to do and have hit a road block. In short, I have two input fields (form) in html that needs to be verified for numerals, find all the numbers in between, add all the numbers and give an output to the user. Also, the two fields can have the numbers 1 and 10, or 10 and 1, and give the same output. Here's a quick description:

first number: 1
last number: 10
The sum of the numbers in the range is 55 (1+2+3+4+5...)

I apologize, I don't know how to use the tag feature, but here's what I have for code thus far:

<?php // Script - test2.php


// Check if the form has been submitted.

if (isset($_POST['submitted'])) {

if (is_numeric($_POST['a']) && is_numeric($_POST['b'])) {

	// Print the heading.
	echo '<h1><font color="blue">Sum of Range</font></h1>';

	$total = NULL; // Initialize $total.

	if ($a <= $b) {
		for ($i = $a; $i <= $b; $i++) {
		$total = $total + $i;
		}
		echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total .'.</font></p>';
	} elseif ($a > $b) {
		for ($i = $a; $i >= $b; $i--) {
		$total = $total + $i;
		}
		echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total .'.</font></p>';
	}

	//echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is  ' . $total . '.</font></p>';

	// Print some spacing.
	echo '<p><br /></p>';

} else { // Invalid submitted values.
	echo '<h1><font color="red">Error!</font></h1>
	<p class="error"><font color="red"><b>Please enter a valid number for a and b.</b></font></p><p><br /></p>';
}

} // End of main isset() IF.

// Leave the PHP section and create the HTML form.
?>
<html>
<body>
<h2>Sum of a Range of Numbers</h2>
<form action="test3.php" method="post">
	<p>First Number: <input type="text" name="a" size="5" maxlength="10" value="<?php if (isset($_POST['a'])) echo $_POST['a']; ?>" /></p>
	<p>Last Number: <input type="text" name="b" size="5" maxlength="10" value="<?php if (isset($_POST['b'])) echo $_POST['b']; ?>" /></p>
	<p><input type="submit" name="submit" value="Calculate!" /></p>
	<input type="hidden" name="submitted" value="TRUE" />
</form>
</body>
</html>

If I enter 1 and 10 into my form, I get a response that the $total is equal to 0, and it does post. I'm guessing that I need to keep the $total variable as it runs through the process of increasing or decreasing the value, but I have yet to have any success. I have tried a few global functions, as well as different else-if statements. If I use $_GET['$total'] instead of just $total in the echo statements, it's blank.

I hope this makes sense and appreciate your time and assistance!

Dan

NogDog

Looks like you might be running on a host which (correctly) has register_globals turned off. Therefore you must reference the input values as $_POST['a'] (as you do in some places), not simply as $a.

Hootnholler

NogDog, 😃

Thank you, thank you, thank you! You have no idea how much I appreciate your immediate and accurate response!

I changed the $a and $b to $POST['$a'] and $POST['$b'] respectively and it works like a champ.

Here's the new code, if anyone is interested...

<?php // Script - test3.php


// Check if the form has been submitted.

if (isset($_POST['submitted'])) {

if (is_numeric($_POST['a']) && is_numeric($_POST['b'])) {

	// Print the heading.
	echo '<h1><font color="blue">Sum of Range</font></h1>';

	$total = NULL; // Initialize $total.

	if ($_POST['a'] <= $_POST['b']) {
		for ($i = $_POST['a']; $i <= $_POST['b']; $i++) {
		$total = $total + $i;
		}
		echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total .'.</font></p>';
	} elseif ($_POST['a'] > $_POST['b']) {
		for ($i = $_POST['a']; $i >= $_POST['b']; $i--) {
		$total = $total + $i;
		}
		echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total .'.</font></p>';
	}

	//echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is  ' . $total . '.</font></p>';

	// Print some spacing.
	echo '<p><br /></p>';

} else { // Invalid submitted values.
	echo '<h1><font color="red">Error!</font></h1>
	<p class="error"><font color="red"><b>Please enter a valid number for a and b.</b></font></p><p><br /></p>';
}

} // End of main isset() IF.

// Leave the PHP section and create the HTML form.
?>
<html>
<body>
<h2>Sum of a Range of Numbers</h2>
<form action="test3.php" method="post">
	<p>First Number: <input type="text" name="a" size="5" maxlength="10" value="<?php if (isset($_POST['a'])) echo $_POST['a']; ?>" /></p>
	<p>Last Number: <input type="text" name="b" size="5" maxlength="10" value="<?php if (isset($_POST['b'])) echo $_POST['b']; ?>" /></p>
	<p><input type="submit" name="submit" value="Calculate!" /></p>
	<input type="hidden" name="submitted" value="TRUE" />
</form>
</body>
</html>

I should have posted here earlier, after 20 hours this past weekend of trying to get this... it had to be a server issue...

NogDog, your work is sincerely appreciated!

Hoot

ClarkF1

A neater version using range - it works high to low or low to high. No if statements needed:

<?php // Script - test3.php


// Check if the form has been submitted.

if (isset($_POST['submitted'])) {

if (is_numeric($_POST['a']) && is_numeric($_POST['b'])) {

// Print the heading.
echo '<h1><font color="blue">Sum of Range</font></h1>';

$total = NULL; // Initialize $total.

$numbers = range($_POST['a'],$_POST['b']);

foreach ($numbers as $value)
{
  $total += $value;
}


echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total .'.</font></p>';


//echo '<p><font color="blue">The sum of the range of numbers from ' . $_POST['a'] . ' to ' . $_POST['b'] . ' is ' . $total . '.</font></p>';

// Print some spacing.
echo '<p><br /></p>';

} else { // Invalid submitted values.
echo '<h1><font color="red">Error!</font></h1>
<p class="error"><font color="red"><b>Please enter a valid number for a and b.</b></font></p><p><br /></p>';
}

} // End of main isset() IF.

// Leave the PHP section and create the HTML form.
?>
<html>
<body>
<h2>Sum of a Range of Numbers</h2>
<form action="test3.php" method="post">
<p>First Number: <input type="text" name="a" size="5" maxlength="10" value="<?php if (isset($_POST['a'])) echo $_POST['a']; ?>" /></p>
<p>Last Number: <input type="text" name="b" size="5" maxlength="10" value="<?php if (isset($_POST['b'])) echo $_POST['b']; ?>" /></p>
<p><input type="submit" name="submit" value="Calculate!" /></p>
<input type="hidden" name="submitted" value="TRUE" />
</form>
</body>
</html>

Hootnholler

Hi Clark, 😃

You are absolutely correct... that was one of our teachings, was to use the for statements like I did or a foreach as you had posted. I was unable to get my script to work (initially) with the foreach statement, and your answer provided some great insight!

I apologize, these are my first postings on here and I did figure out how to mark the thread resolved. Thank you for your posting and thank you again for the reminder! This is a great resource!

Hoot

laserlight

By the way, $total should be initialised to 0, not NULL.