Hex to string

int CharToHex(const char ch)
{
const char Hex[] = "0123456789ABCDEF";
for (int n = 0; Hex[n]; ++n)
{
   if (ch == Hex[n])
   {
       return n;
   }
}
return 0;
}

UINT64 StringToHex(const char* c)
{
UINT64 l = 0;
for (int n = 0; c[n]; ++c)
{
   l = l * 16 + CharToHex(c[n]);
}
return l;
}