Перевод из 16-ой системы счисления в 10-ю - C (СИ)

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <stdio.h>

int HEX_TO_DEC(char st[10])
{
    int i, s, k, p;
    s = 0;
    p = strlen(st) - 1;
    for (i = 0; st[i] != '\0'; i++)
    {
        switch (toupper(st[i]))
        {
            case 'A':
                k = 10;
                break;
            case 'B':
                k = 11;
                break;
            case 'C':
                k = 12;
                break;
            case 'D':
                k = 13;
                break;
            case 'E':
                k = 14;
                break;
            case 'F':
                k = 15;
                break;
            case '1':
                k = 1;
                break;
            case '2':
                k = 2;
                break;
            case '3':
                k = 3;
                break;
            case '4':
                k = 4;
                break;
            case '5':
                k = 5;
                break;
            case '6':
                k = 6;
                break;
            case '7':
                k = 7;
                break;
            case '8':
                k = 8;
                break;
            case '9':
                k = 9;
                break;
            case '0':
                k = 0;
                break;
        }
        s = s + k * pow(16, p);
        p--;
    }
    printf("%d, &s") ;
    return 0;
}
 
void main()
{
    char s[10];
    char ch;
    printf ( "Plese, enter string: \n");
    scanf("%s,  &s")  ;
    printf ("Rezultant: \n");
    HEX_TO_DEC(s);
    scanf ();
}