How to make 5 conditional with only 1 if 2 else if 1 else?

Question

I have a certain conditional like below.

>80 category A
71-80 category AB 
51-70 category B
41-50 category BC 
<40 category C

I need to make a code that meet above condition. But only with 1 if 2 else if 1 else

I figured out that i need to set the default category value, but it still does not meet the expected result

$category= "C";
$value = "10";

if ($value > 80) {
  $category = "A";
}else if ($value <= 70 AND $value > 50) {
  $category = "B";
}else if ($value <= 80 AND $value > 70) {
  $category = "AB";
}else{
  $category = "BC";
}

echo $category;

i want to make output like this

90 = A 
72 = AB
55 = B 
45 = BC
10 = C 

but my code show below

90 = A 
72 = AB
55 = B 
45 = BC
10 = BC 

Answer 1

If the point is to limit the keywords if, else and else if, you can use ternary operator in the last else.

function getCat($val)
{
    $cat = '';

    if ($val >= 81) {
        $cat = 'A';
    } else if ($val >= 71 && $val <= 80) {
        $cat = 'AB';
    } else if ($val >= 51 && $val <= 70) {
        $cat = 'B';
    } else {
        $cat = $val < 40 ? 'C' : 'BC';
    }

    return $cat;
}

Here's a demo

There's one issue though. If the value is 40, this would give it BC, but you never wrote any rule for that number so it is what it is