How can I get the next letter alphabetically without incrementing? (php)

Question

for ($i=A;$i<L;$i++){                   
    echo $i;
    echo '->';
    echo ++$i;
    echo ', ';
}

gives me:

A->B, C->D, E->F, G->H, I->J, K->L

what I want is:

A->B, B->C, C->D, D->E, E->F, F->G

What's the simplest way to do this?

Answer 1

Simple:

for ($i=A;$i<L;){  // remove loop increment                 
    echo $i;
    echo '->';
    echo ++$i;
    echo ', ';
}