Question: How do I determine if a `char` in C such as `a` or `9` is a number or a letter?

Is it better to use:

```
int a = Asc(theChar);

```

or this?

```
int a = (int)theChar

```

Answer: 
You'll want to use the `isalpha()` and `isdigit()` standard functions in `<ctype.h>`.

```
char c = 'a'; // or whatever

if (isalpha(c)) {
    puts("it's a letter");
} else if (isdigit(c)) {
    puts("it's a digit");
} else {
    puts("something else?");
}

```
If `(theChar >= '0' && theChar <='9')` it's a digit. You get the idea.