How do I read hex numbers into an unsigned int in C

Question

I\'m wanting to read hex numbers from a text file into an unsigned integer so that I can execute Machine instructions. It\'s just a simulation type thing that looks inside

Answer 1

Do you want each of the lines (each 4 characters long) separated in 4 different array elements? If you do, I'd try this:

/* read the line */
/* fgets(buf, ...) */

/* check it's correct, mind the '\n' */
/* ... strlen ... isxdigit ... */

/* put each separate input digit in a separate array member */
num[i++] = convert_xdigit_to_int(buf[j++]);

Where the function convert_xdigit_to_int() simply converts '0' (the character) to 0 (an int), '1' to 1, '2' to 2, ... '9' to 9, 'a' or 'A' to 10, ...

Of course that pseudo-code is inside a loop that executes until the file runs out or the array gets filled. Maybe putting the fgets() as the condition for a while(...)

while(/*there is space in the array && */ fgets(...)) {
}