value of variable vanishes - php

Question

I do not understand what is happening with my variables, the values all vanish / become empty within the function. I don't have anything within the function. I believe that I am doing the 'checks' correctly '==' and the assignments correctly '='. Regardless of what i try, i continue to get the 'file doesn't exist result'. and if i var_dump to see what the value of $cID or $check, they come back as empty ''.
function gt_masthead($cID='3', $check=false, $str=''){ //assign value to var
$check == file_exists('./' . $cID . 'bg-userProfile.jpg'); //file exists?
//echo '<h1> / ' . $cID . ' / ' . $check . ' </h1>';
dumpVar($cID); //test
if($check == 1){
// file exists, show
$str = '<img class=" img-fluid" style="width: 100%;" src="./3bg-userProfile.jpg" alt="Card image cap">';
}else{
// file does not exist, show default
$str = '<img class=" img-fluid" style="width: 100%;" src="./img_logoMarvel.gif" alt="Card image cap">';
}
return $str;
}

Answer 1

Try this code instead:
<?php
function gt_masthead($cID, $image = "bg-userProfile.jpg", $default = "img_logoMarvel.gif") { //assign value to var
//check if given image file exists
if(file_exists("./{$cID}{$image}")) {
//if it does exist, set the displayImage variable to the path of the image.
$displayImage = "./{$cID}{$image}";
} else {
//if it does not exist, set the displayImage variable to the path of the default image
$displayImage = "./{$default}";
}
//Add the displayImage path to an image element, and return that element.
$str = "<img class='img-fluid' style='width:100%;' src='{$displayImage}' alt='Card image cap'>";
return $str;
}
?>
The usage of this code is pretty simple. You call it like this:
gt_masthead("cID number", "image name"); - you can also use variables here, just drop the quotes.
Alternatively, you can also use a 3rd variable to dynamically set the default image if the searched one does not exist.
gt_masthead("cID number", "image name", "default image name");
I commented the code to try to explain what is going on. If you have any questions please ask
Here is a more standard way to write the function, I know the squiggly braces sometimes confused people, but the code is basically the same.
<?php
function gt_masthead($cID, $image = "bg-userProfile.jpg", $default = "img_logoMarvel.gif") { //assign value to var
//check if given image file exists
if(file_exists("./".$cID.$image)) {
//if it does exist, set the displayImage variable to the path of the image.
$displayImage = "./".$cID.$image;
} else {
//if it does not exist, set the displayImage variable to the path of the default image
$displayImage = "./".$default;
}
//Add the displayImage path to an image element, and return that element.
$str = "<img class='img-fluid' style='width:100%;' src='".$displayImage."' alt='Card image cap'>";
return $str;
}
?>