/*
    testfunc14.cpp
    CIS 150
    2008-06-10
    David Klick
   
    This program demonstrates a useful data validation
    function for use with menus.
*/

#include <iostream>
#include <cctype>
using std::cin;
using std::cout;

char getChoice(char* prompt, char* allowed);
void displayChoice(char* msg);
void cont();

int main(int argc, char* argv[]) {
    char choice;
    do {
        // display menu
        cout << "Menu\n\n"
                "    (F)irst\n\n"
                "    (S)econd\n\n"
                "    (E)nd\n\n";

        // get user choice
        choice = getChoice("Enter choice: ", "FfSsEe");
        choice = toupper(choice);  // convert to upper case

       // process choice
       switch (choice) {
       case 'F':
           displayChoice("the first choice");
           break;
       case 'S':
           displayChoice("the second option");
           break;
        }
    } while (choice != 'E');

    cout << "Normal program terminiation\n\n";
    cont();
    return 0;
}

/*
    char getChoice(char* prompt, char* allowed);
   
    Arguments:
        char* prompt: a C-style string containing the prompt to show the user
        char* allowed: a C-style string containing all allowed user responses
            (each valid response being a single character)
   
    Returns: the user's choice (a character)
   
    Displays a prompt and then waits for the user to
    enter an allowed choice (a single character). Once
    a valid choice has been made, the function returns
    it to the calling function.
*/
char getChoice(char* prompt, char* allowed) {
    char ch;
    char *ptr;
    do {
        cout << prompt;
        cin >> ch;
        ptr = strchr(allowed, (int)ch);
        if (ptr == NULL) {
            cout << "Error: Invalid choice\n";
        }
    } while (ptr == NULL);
    return ch;
}

/*
    void displayChoice(char* msg);
   
    Arguments:
        char* msg: a pointer to a C-ctyle string to be displayed
   
    Returns: nothing
   
    Displays a string sent in as being what the user has chosen.
*/
void displayChoice(char* msg) {
    cout << "You chose " << msg << '\n';
}

/*
    void cont();
   
    Arguments: none
   
    Returns: nothing
   
    Clears input buffer and pauses waiting for user 
    to press Enter.
*/
void cont() {
    if (cin.rdbuf()->sungetc() != -1 && cin.get() != '\n') cin.ignore(80,'\n');
    cout << "Press enter to continue...";
    cin.get();
}