Implementing a proper reading from file

[Micard]

I feel very dumb right now, so please, don't add up to this :) I'd PM one of the forum members, but he doesn't accept PM (Horscht).

I'll just give you full code in order to get a clear understanding of what the program does. So here you're looking at two functions: savelist() and loadlist(). Function savelist() works just fine, but I'm having troubles with implementing the loading system. I don't want to just print whatever is in the file, but to create a new list out of it. I guessed it works just like function addPassenger(), but the problem here is how to read it. So could you please take a look at this humiliation and give me an advice? Thank you!

#include <cstdio>
#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;

#define PASSENGER_NAME 36
#define FLIGHTS_NUM 5
#define SEATS_NUM 24

struct Passenger {
	char name[PASSENGER_NAME];
	char flight[FLIGHTS_NUM];
	int seat_num;
	float price_paid;
	
	Passenger *next;
};

bool isEmpty(Passenger *head);
char menu();
void insertAsFirst(Passenger *&head, Passenger *&last, char *p_name, 
					char *p_flight, int p_seat_num, float p_price_paid);
void addPassenger(Passenger *&head, Passenger *&last, char *p_name, 
					char *p_flight, int p_seat_num, float p_price_paid);
void removePassenger(Passenger *&head, Passenger *&last);
void showlist(Passenger *current);
void savelist(Passenger *current);
void loadlist(Passenger *&head, Passenger *&last);


bool isEmpty(Passenger *head)
{
	if (head == NULL)
		return true;
		else return false;
}

char menu()
{
	char choice;
	printf("\nOption: ");
	scanf("%c", &choice);
	
	return choice;
}

void insertAsFirst(Passenger *&head, Passenger *&last, char *p_name, 
					char *p_flight, int p_seat_num, float p_price_paid)
{
	Passenger *temp = new Passenger;
	strcpy(temp->name, p_name);
	strcpy(temp->flight, p_flight);
	temp -> seat_num = p_seat_num;
	temp -> price_paid = p_price_paid;
	temp -> next = NULL;
	head = temp;
	last = temp;
}

void addPassenger(Passenger *&head, Passenger *&last, char *p_name, 
					char *p_flight, int p_seat_num, float p_price_paid)
{
	if(isEmpty(head))
		{
	insertAsFirst(head, last, p_name, p_flight, p_seat_num, p_price_paid);
	}
		else {
			Passenger *temp = new Passenger;
			strcpy(temp->name, p_name);
			strcpy(temp->flight, p_flight);
			temp -> seat_num = p_seat_num;
			temp -> price_paid = p_price_paid;	
			temp -> next = NULL;
			last -> next = temp;
			last = temp;
		}
}

void removePassenger(Passenger *&head, Passenger *&last)
{
	if(isEmpty(head))
		printf("Error: The list is already empty!\n");
		else if (head == last)
		{
			delete head;
			head = NULL;
			last = NULL;
		}
		
		else 
		{
			Passenger *temp = head;
			head = head -> next;
			delete temp;
		}
}

void showlist(Passenger *current)
{
	if(isEmpty(current))
		printf("Error: Cannot display list because it is empty!\n");
		else 
			{
				printf("Passengers: \n");
				while(current != NULL)
				{
				 printf("\nName: %s\nFlight: %s\nSeat: %d\nPaid: %.2f\n", current -> name, current -> flight, 
																	current -> seat_num, current -> price_paid);
				 printf("\n");
				 current = current -> next;
				}
			}
}

void savelist(Passenger *current)
		{
			
			if(isEmpty(current))
				printf("Error: Cannot save data, the list is empty!\n");
			else 
			{
				ofstream pass_list;
				pass_list.open("passlist.txt");
				while(current != NULL)
				{
				 pass_list << current -> name << " " << current -> flight << " " 
									<< current -> seat_num << " " << current -> price_paid;
				 pass_list << "\n";
				 current = current -> next;
				}
				pass_list.close();
			}
			
		}

void loadlist(Passenger *&head, Passenger *&last)
{
			        char p_name[PASSENGER_NAME];
			        char p_flight[FLIGHTS_NUM];
				int p_seat_num;
				float p_price_paid;
				ifstream pass_list("passlist.txt");
				if (pass_list.is_open())
					{
				while (pass_list >> p_name >> p_flight >> p_seat_num >> p_price_paid)
				{

				Passenger *temp = new Passenger;
				strcpy(temp->name, p_name);
				strcpy(temp->flight, p_flight);
			        temp -> seat_num = p_seat_num;
				temp -> price_paid = p_price_paid;
				temp -> next = NULL;
				head = temp;
				last = temp;
	
				}
				pass_list.close();
					} else cout << "Error: Unable to open file!\n"; 
}

int main(int argc, char **argv)
{
			//Used for menu manipulations
			char choice;
			char name[PASSENGER_NAME];
			char flight[FLIGHTS_NUM];
			int seat_num = 0;
			float price_paid = 0;
	
			Passenger *head = NULL;
			Passenger *last = NULL;
	
	
			printf("Menu: \n1.Add a Passenger\n2.Remove a Passenger\n3.Show List of Passengers\n4.Save to file\n5.Load from file\n6.Exit\n");
	
			do {
			choice = menu();
			switch(choice)
				{
					case '1':  cout << "Name: ";
							   cin >> name;
							   cout << "\nFlight: ";
							   cin >> flight;
							   cout << "\nSN: ";
							   cin >> seat_num;
							   cout << "\nPaid: ";
							   cin >> price_paid;
							addPassenger(head, last, name, flight, seat_num, price_paid);
					break;
			case '2': removePassenger(head, last);
					break;
			case '3': showlist(head);
					break;
			case '4': savelist(head);
					break;
			case '5': loadlist(head, last);
					break;
			default: printf("\n");
		}
		
		
	} while (choice != '6');
	
	return 0;
}

[Micard]

And the thing is - it does work. Kind of. Barely. It reads only the last line. It does record seat_num and price_paid into the list and even displays it. Whoever saw this problem earlier - yeah, it's the thing with names and flights again + reading line by line. I tried a couple methods already, but it wouldn't work.

[Micard]

Oh wait, I fixed it. Just had to replace some things. Okay, now how do I read line by line and insert passengers as they go in the file, i.e. 1st, 2nd, 3rd... etc?

[Micard]

Up. Still not solved. The question is - how do I read the passlist.txt line by line? I tried different loops but they only reset the place where it reads the file - either from the beginning of the file or from its end.