I'm doing an exercise, to practice, where the point is to receive a string of numbers and letters, check if it's a letter, transforme it to number with the rule

```
A = 10, Z = 35

```

and then place everything in an array. Some operations after.

I know how to do everything except the rule part, no idea about how to check which letter it is and how to replace it with the right number. I know there's a way with something like

```
     if(string[x] == 'a-Z')

```

but i'm neither sure how that works, or how to pick the right number knowing that it's a letter.