title: Convert a string of hexadecimal digits into integer
body: <p>I am trying to implement the htoi(s) [Dennis Ritchie chapter2 exercise 2-3 Q] which converts a string of hexadecimal digits, into its equivalent integer, can anyone help me out in the logic of this program, i dont need the code, i just need the logic for implementing it. I am not able to get the correct logic</p>