hexa_to_binary.c

#include "base.h"
/**
 * hex_to_bin - This function converts hexadecimal to binary
 * @hexa: hexadecimal argument
 * Return: Return (0) on success. (-1) for otherwise
*/

int hex_to_bin(const char *hexa)
{
    int decimal, power, len;
    decimal = 0;
    power = 0;
    char value;
    len = strlen(hexa) - 1; // length of string to use

    while(len >= 0) // loop breaks when len is less than 0
    {
        if (isdigit(hexa[len])) // if its a digit
        {
                value = hexa[len];
                decimal += (value - '0') * pow(16, power); // substract the ascii value of 0(48)
        }
        if (isalpha(hexa[len]))
        {
            value = tolower(hexa[len]);
            if (value >= 97 && value <= 102)
            {
                decimal += (value - 'a' + 10) * pow(16, power);
            }
            else
            {
                //Handle error
                dprintf(2, "Only valid Hexadecimal characters\n"); 
                return (-1);
            }
        }
        len--;
        power++;
    }

    dec_to_bin(decimal); // we call the function that can convert decimal to binary
}