Division with Arrays - php

Question

<?php
$txtfield = $_POST['number1'];
$arr = explode(' ',trim($txtfield));
$operator = $arr[0];
$count=count($arr);
$sum = array_sum($arr);
echo "Sum of the number:".$sum. "<br>";
$prod=1;
for ($i=1; $i<$count; $i++){
$prod = $prod * $arr[$i];}
echo "Product of the numbers:".$prod."<br>";
$diff=$arr[1];
for ($i=1; $i<$count; $i++){
$diff= $diff - $arr[$i+1];
}
echo "Difference of the numbers:".$diff."<br>";
$div=$arr[1];
foreach ($i=1; $i<$count; $i++){
$div=$div / $arr[$i];
}
echo "Qoutient of the numbers:". $div. "<br>";
?>
This line of code doesn't seem to work properly. When I entered 10 & 5 the output is:
Sum of the number:15
Product of the numbers:50
Difference of the numbers:5
Qoutient of the numbers:0.2

Answer 1

Assuming that by I entered 10 & 5 you mean that $arr looks like this:
$arr = array(
1 => 10,
2 => 5
);
...then 0.2 is the expected result of the quotient. This is what your code does:
$div = 10;
$div = 10 / 10; // 1
$div = 1 / 5; // 0.2
I think that you meant to initialise $i at 2. This will give your expected output. But a better approach would be this:
$arr = array(
10,
5
);
// Make a copy of $arr before this if you need the original data intact
$quotient = array_shift($arr);
foreach ($arr as $val) {
$quotient /= $val;
}
Now the element indexes are irrelevant, only the element order is significant.
EDIT
Here is how I would write your newly posted full code:
// Split on any number of whitespace characters to avoid bad user input
$arr = preg_split('/\s+/', $_POST['number1']);
// Remove the first element of the array so it doesn't interfere with calculations
$operator = array_shift($arr);
// This is fine
$sum = array_sum($arr);
// Product has a function of it's own
$prod = array_product($arr);
// Difference and quotient can be done in one loop
$diff = $quot = array_shift($arr);
foreach ($arr as $val) {
$diff -= $val;
$quot \= $val;
}
// Echo the results
echo "Sum of the number:".$sum."<br>";
echo "Product of the numbers:".$prod."<br>";
echo "Difference of the numbers:".$diff."<br>";
echo "Qoutient of the numbers:".$quot."<br>";

Answer 2

I've reformatted your program and added static values so that it will execute standalone.
<?php
$arr = array(10, 5);
$count = count($arr);
$sum = array_sum($arr);
echo 'Sum of the number: '.$sum."<br>\n";
$prod = 1;
for($i = 0; $i < $count; $i++)
{
$prod *= $arr[$i];
}
echo 'Product of the numbers: '.$prod."<br>\n";
$diff = $arr[0];
for($i = 1; $i < $count; $i++)
{
$diff -= $arr[$i];
}
echo 'Difference of the numbers: '.$diff."<br>\n";
$div = $arr[0];
for($i = 1; $i < $count; $i++)
{
$div /= $arr[$i];
}
echo 'Quotient of the numbers: '.$div."<br>\n";
?>
The output of this program is:
Sum of the number: 15
Product of the numbers: 50
Difference of the numbers: 5
Quotient of the numbers: 2