This is a program my instructor wrote and I have to create a program that similar in format. My issue is I don't quite understand what main is doing or how it works, was hoping someone could explain it to me in detail.
Rolodex.h
#ifndef _ROLODEX_H_
#define _ROLODEX_H_
#include "card.h"
#include <iostream>
#include <fstream>
#include <stdlib.h>
using namespace std;
class rolodex
{
private:
fstream file;
public:
rolodex() // constructor opens the file
{
// input and output stream
file.open("rolodex.txt", ios::in | ios::out | ios::app);
if (!file.good())
{
cerr << "ERROR: unable to open \"rolodex.txt\"\n";
exit(1);
}
}
~rolodex() // destructor flushes and closes the file
{
file.flush();
file.close();
}
void interactive();
char menu();
void search();
void search(char* name);
void enter();
void enter(char* name, char* address, char* phone);
int read(card deck[]);
void print(card* entry) { entry->print(); }
void list();
int sort(card* list);
};
#endifCard.h
#ifndef _CARD_H_
#define _CARD_H_
/*
* An instance of the card class represents one card in a rolodex file.
* Each card contains the contact information for one person as a set of three c-strings:
* name, address, and phone number.
*/
// prevent warning about Microsoft deprecated c-string functions
#define _CRT_SECURE_NO_DEPRECATE
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
enum sizes { NAME_SZ = 20, ADDR_SZ = 40, PHONE_SZ = 15 }; // the sizes of card fields
class card
{
private:
char name[NAME_SZ];
char address[ADDR_SZ];
char phone[PHONE_SZ];
public:
card()
{
name[0] ='\0';
address[0] ='\0';
phone[0] ='\0';
}
card(char* n, char* a, char* p)
{
strcpy(name, n);
strcpy(address, a);
strcpy(phone, n);
}
card(char* line)
{
strcpy(name, strtok(line, ":"));
strcpy(address, strtok(NULL, ":"));
strcpy(phone, strtok(NULL, ":"));
}
void print()
{
cout.setf(ios::left);
cout << setw(NAME_SZ) << name;
cout << setw(ADDR_SZ) << address;
cout << setw(PHONE_SZ) << phone << endl;
}
friend int card_comp(const void* c1, const void* c2);
};
#endifRolodex.cpp
#define _CRT_SECURE_NO_DEPRECATE
#include "card.h"
#include "rolodex.h"
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
int main(int argc, char* argv[])
{
rolodex contacts;
if (argc == 1) // no arguments ==> enter interactive mode
contacts.interactive();
else if (argc == 2 && !strcmp(argv[1], "-l"))
contacts.list();
else if (argc == 2)
contacts.search(argv[1]); // 1 arg ==> search for arg and quit
else if (argc == 4)
contacts.enter(argv[1], argv[2], argv[3]); // 3 args > new entry & quit
else
cerr << "USAGE: rolodex | rolodex -l | rolodex <name> | rolodex <name> <address> <phone>\n";
return 0;
}
// prints a short menu and reads the user's choice
char rolodex::menu()
{
system("cls");
cout << "S\t Search For A Name \n";
cout << "E\t Enter A New Name \n";
cout << "L\t List All Entries \n";
cout << "Q\t Quit \n";
cout << "\n\nCommand: ";
char command;
cin >> command;
cin.ignore(); // discard the new line
return command;
}
// interactive mode displays a menu and does what the user want until the program ends
void rolodex::interactive()
{
while (true)
{
char operation = menu();
switch (operation)
{
case 's' : // search
case 'S' :
search();
system("pause");
break;
case 'e' : // enter
case 'E' :
enter();
break;
case 'l' : // list
case 'L' :
list();
system("pause");
break;
case 'q' : // quit
case 'Q' :
exit(0);
default:
cerr << "Unknown option: " << operation << endl;
break;
}
}
}
// prompts for a search name and searches
void rolodex::search()
{
char name[NAME_SZ];
cout << "Please enter the search name: ";
cin.getline(name, NAME_SZ);
search(name);
}
// searches for the given name
void rolodex::search(char* name)
{
card list[50];
int count = sort(list);
card key(name, "", "");
card* entry = (card *)bsearch(&key, list, count, sizeof(card), card_comp);
if (entry != NULL)
print(entry);
else
cout << name << " was not found in the Rolodex\n";
}
// reads all data from the rolodex file in a list of rolodex cards
int rolodex::read(card deck[])
{
file.clear(); // clear EOF -- MUST come before seek
file.seekg(0); // return to beginning of file
int count = 0;
char line[100];
while (file.getline(line, 100))
{
deck[count] = card(line);
count++;
}
return count;
}
// prompts for data to create a new entry in the rolodex file
void rolodex::enter()
{
char name[NAME_SZ];
char address[ADDR_SZ];
char phone[PHONE_SZ];
cout << "Please enter the new name: ";
cin.getline(name, NAME_SZ);
cout << "Please enter the new address: ";
cin.getline(address, ADDR_SZ);
cout << "Please enter the new phone #: ";
cin.getline(phone, PHONE_SZ);
enter(name, address, phone);
}
// enters a new card into the rolodex file
void rolodex::enter(char* name, char* address, char* phone)
{
file.clear(); // clear EOF
file.seekp(0, ios::end); // move to end of file
file << name << ":" << address << ":" << phone << endl;
file.flush();
}
// lists all data in the rolodex file
void rolodex::list()
{
card list[50];
int count = sort(list);
for (int i = 0; i < count; i++)
print(&list[i]);
}
// reads and sorts a list of rolodex cards
int rolodex::sort(card* list)
{
int count = read(list);
qsort(list, count, sizeof(card), card_comp); // sorts a list of rolodex cards
return count;
}
// alphabetically compares two rolodex cards
// returns < 0 if c1 comes before c2
// returns 0 if c1 == c2
// returns > 0 if c1 comes after c2
int card_comp(const void* c1, const void* c2)//compares the names on two rolodex cards
{
return strcmp(((card *)c1)->name, ((card *)c2)->name);
}