How to add integers to a PHP variable - php

Question

I'm trying to create a sorting algorithm based off a query. Essentially the user would input values for Height, Weight, and a few other attributes. I am then querying our database of models to match that person with someone who has the closest measurements to those that the user inputted. I'm trying to do this based off a weighted variable that I am assigning within the "while" statement of the query and then returning that variable's value at the end. Here is some code to show you what I mean:
$userHeight=$_POST['height'];
$userWeight=$_POST['weight'];
$userShoulder=$_POST['shoulder'];
$userWaist=$_POST['waist'];
$userInseam=$_POST['inseam'];
$heightMatchMultiple=0;
$heightMatchMultiple=0;
$weightMatchMultiple=0;
$shoulderMatchMultiple=0;
$waistMatchMultiple=0;
$inseamMatchMultiple=0;
function matchValues($array){
if(mysqli_num_rows($array) > 0) {
while($row=mysqli_fetch_array($array)){
$heightMatchMultiple=0;
if(isset($row['modelHeight'])){
if($userHeight==$row['modelHeight']){
$heightMatchMultiple=10;
}
elseif($userHeight==$row['modelHeight']+1 || $userHeight==$row['modelHeight']-1){
$heightMatchMultiple=9;
}
elseif($userHeight==$row['modelHeight']+2 || $userHeight==$row['modelHeight']-2){
$heightMatchMultiple=8;
}
elseif($userHeight==$row['modelHeight']+3 || $userHeight==$row['modelHeight']-3){
$heightMatchMultiple=7;
}
else{
$heightMatchMultiple=1;
}
}
echo "Model Match Multiple: " . $heightMatchMultiple . "<br>";
}
}//end of if num rows
else {
echo "No results to display.";
}
}//end of function
When I run this function, it is returning the else statement's value for heightMatchMultiple of 1 instead of 10 because there is a model in the database with a height of 69 which is what I used as user input.
Can I add +1 or +2 directly to the $row['modelHeight'] variable as I did or is there a better way to do this.
EDIT:
Some people were asking where I initialized the variable $userHeight so i added it to the code. I tried creating global variables for $heightMatchMultiple=0 as a way to make those variables usable within my matchValues function. Is this correct?

Answer 1

Where is $userHeight being initialized/passed in? I think the reason you're currently getting 69 is because $userHeight has not been set, hence it gets a value of zero by default, which means that 1 will be the correct answer if $row['modelHeight'] is 69.
To answer your real question, which is really about order of operations: yes, what you have written should do what I believe you are trying to achieve. However, you should probably add parenthesis, even though they aren't strictly necessary, just as a hint to your future self that you really did intend for the calculations to happen in a certain order.
For example, instead of this:
elseif($userHeight == $row[ 'modelHeight' ] + 1 || $userHeight == $row[ 'modelHeight' ] - 1)
you could write this:
elseif(($userHeight == ( $row[ 'modelHeight' ] + 1 )) || ( $userHeight == ( $row[ 'modelHeight' ] - 1)))
Or you could re-write each of the checks using abs() like this:
elseif(abs($userHeight - $row['modelHeight']) == 1 )
This is arguably more descriptive, since what you're really trying to say is "if the difference is 1".
But yes, you can use the + 1 and +2 etc as in your original code, but you do need to set or pass in the $userHeight variable at some point.