C++ :: Add Each Number From Zip Code Inputted By User

I came up with this code to try to add each number from a zip code inputted by the user but I think I'm adding up the ascii values not the real values the user is inputting. How I can go from ascii to the real digit. This is my code so far

#include <iostream>
#include <iomanip>
#include <string>
#include <conio.h>
using namespace std;
int main() {
int total = 0;
char ch[5];

cout << "Please input your 5 digit zip code: ";

[Code] ....