List all linked list

[Hidden Squid]

hello,

I am in the middle of finishing up this code and when i run through the list all it crashes and visual basic throws a exception, but what is happening is that it is listing it all then it will go to nullptr and then crash because there is nothing there. How do i go about fixing this? I have been at this for a while now

[Hidden Squid]

lab5class.cpp

#include "lab5header.h" 
#include <iostream>
#include <fstream>
#include <iomanip>
/************************************************/
//
//
//
//Lab4(No leaks)
//
//
//
//
/***********************************************/
//initialize pointer
starFleet::starFleet()
{
	//for (int i = 0; i < FLEET_SIZE; i++)
	//{
	//	Ships[i] = NULL; // RM, changed from ships to Ships, as per your class.
	//}
	shipCount = 0;
	head = nullptr;
}
starFleet::~starFleet()
{
    shipData * temp;
    // RM, delete the linked list.
	while(head != nullptr)
	{
		delete[] head->name;
		delete[] head->type;
		delete[] head->position;
		delete[] head->condition;
		delete[] head->captain;
        delete head;
		temp = head->next;
        head = temp;
	}
}
void starFleet::loadData()
{
	shipData * tempShip, *cur, *next;
	shipCount = 0; //set the count = 0
	ifstream inputFile;
	cout << "Loading Data file......." << endl;
	inputFile.open("starships.txt");
	char tempString[S_SIZE];  // RM, temporary holder for input info.
	while (!inputFile.eof())
	{
		tempShip = new shipData;  // RM, Set aside data for a new ship.
		inputFile.getline(tempString, S_SIZE, ';');
		tempShip->name = new char[strlen(tempString) + 1]; // RM, Set up the data for name, just the right size.
		strcpy(tempShip->name, tempString);  // RM, Copy the name info into the name array.
		inputFile >> tempShip->regNum;
		inputFile.ignore();
		inputFile.getline(tempString, S_SIZE, ';');
		tempShip->type = new char[strlen(tempString) + 1]; // RM, Set up the data for name, just the right size.
		strcpy(tempShip->type, tempString);
		inputFile.getline(tempString, S_SIZE, ';');
		tempShip->position = new char[strlen(tempString) + 1]; // RM, Set up the data for name, just the right size.
		strcpy(tempShip->position, tempString);
		inputFile.getline(tempString, S_SIZE, ';');
		tempShip->condition = new char[strlen(tempString) + 1]; // RM, Set up the data for name, just the right size.
		strcpy(tempShip->condition, tempString);
		inputFile.getline(tempString, S_SIZE, '\n');
		tempShip->captain = new char[strlen(tempString) + 1]; // RM, Set up the data for name, just the right size.
		strcpy(tempShip->captain, tempString);
		shipCount++;
        
        //  here is where you add a new ship to the linked list, just like addstarship.
        // I'll get you started with the head pointer.
		if (head == nullptr)
		{
			head = tempShip;
		}
		else
		{
			if (head->name > tempShip->name)
			{
				next = head;
				tempShip->next = next;
				
			}
			else
			{
				cur = tempShip;
				next = head->next;
				while (next != nullptr)
				{
					if ((cur->name <= tempShip->name))
					{
						cur->next = head;
						tempShip->next = next;
						break;
					}
					else 
					{
						cur = next;
						next = next->next;
					}
				}
				if (next == nullptr)
				{
					cur->next = tempShip;
				}
			}
			tempShip->next = head;
			head = tempShip;
		}
		
	}
    // RM, moved these lines down.
    inputFile.close();
    cout << endl << "Successfully loaded " << shipCount << " Ships." << endl << endl; // return the total count
    return;
}


void starFleet::addstarship()
{
	//Linked List Data.
	shipData *tempShip, *cur, *next;
	tempShip = new shipData;
	tempShip->next = nullptr;

	fstream file("starships.txt", fstream::app);

	char tempName[S_SIZE];
	cout << " What is the name of the ship ? : ";
	cin.get(tempName, S_SIZE);
	tempShip->name = new char[strlen(tempName) + 1]; // + 1 for null.
	strcpy(tempShip->name, tempName);

	cout << " What is the registry number of the ship ? : ";
	cin >> tempShip->regNum;
	cin.ignore();

	cout << " What is the type of the ship ? : ";
	cin.get(tempName, S_SIZE);
	tempShip->type = new char[strlen(tempName) + 1]; // + 1 for null.
	strcpy(tempShip->type, tempName);
	cin.ignore();

	cout << " What is the position of the ship ? : ";
	cin.get(tempName, S_SIZE);
	tempShip->position = new char[strlen(tempName) + 1]; // + 1 for null.
	strcpy(tempShip->position, tempName);
	cin.ignore();

	cout << " What is the condition of the ship ? : ";
	cin.get(tempName, S_SIZE);
	tempShip->condition = new char[strlen(tempName) + 1]; // + 1 for null.
	strcpy(tempShip->condition, tempName);
	cin.ignore();

	cout << " What is the captain of the ship ? : ";
	cin.get(tempName, S_SIZE);
	tempShip->captain = new char[strlen(tempName) + 1]; // + 1 for null.
	strcpy(tempShip->captain, tempName);
	cin.ignore();
	//  can't use dots with pointers. You have to dereference with (->).
	
	/*************************************************************************/
	//Linked List part of the program. (Lab5)
	//
	//
	//
	//
	/**************************************************************************/
	if (head == nullptr)
	{
		head = tempShip;
	}
	else
	{
		if (head->name > tempShip->name)
		{
			next = head;
			tempShip->next = next;

		}
		else
		{
			cur = tempShip;
			next = head->next;
			while (next != nullptr)
			{
				if ((cur->name <= tempShip->name))
				{
					cur->next = head;
					tempShip->next = next;
					break;
				}
				else
				{
					cur = next;
					next = next->next;
				}
			}
			if (next == nullptr)
			{
				cur->next = tempShip;
			}
		}
		tempShip->next = head;
		head = tempShip;
	}

	file << '\n' << tempShip->name << ';' << tempShip->regNum << ';' <<
		tempShip->type << ';' << tempShip->position << ';' <<
		tempShip->condition << ';' << tempShip->captain;
	shipCount++;
	return;
}

void starFleet::displayFleet()
{
    shipData * cur = head;
	{
		cout << "List all of the fleet!" << endl;
		while(cur != nullptr)
		{
			cout << "-----------------------------------------" << endl;
			cout << "Name of the ship: " << cur->name << endl;
			cout << "Registry number: " << cur->regNum << endl;
			cout << "Type of ship" << cur->type << endl;
			cout << "Position of ship: " << cur->position << endl;
			cout << "Condition of the ship: " << cur->condition << endl;
			cout << "Captain of the ship: " << cur->captain << endl;
			cout << "-----------------------------------------" << endl;
			cur = cur->next;
		}
	}
}
bool starFleet::searchFleet()
{
	int regNum1;
	cout << "Please enter the registry number of the fleet you would like to search for: ";
	cin >> regNum1;
	cin.ignore();
	shipData * cur = head;
	while (cur != nullptr)
	{
		if (cur->regNum == regNum1)
		{
			cout << "Name of the ship: " << cur->name << endl;
			cout << "Registry number: " << cur->regNum << endl;
			cout << "Type of ship" << cur->type << endl;
			cout << "Position of ship: " << cur->position << endl;
			cout << "Condition of the ship: " << cur->condition << endl;
			cout << "Captain of the ship: " << cur->captain << endl;
			cur = cur->next;
			return true;
		}
		else
		{
			cur = cur->next;
		}
		
	}
	if (cur->regNum != regNum1)
	{

		cout << "this ship does not exsist" << endl;
		return false;
	}
}



void starFleet::DeleteShip()
{
	shipData * currentShip, *previousShip, *nextShip;
	char shipName[S_SIZE];
	
	cout << "Delete a Ship." << endl;
	cout << "What is the ship that you would like to Delete?: ";
	cin >> shipName;
	
	bool success = false;
	if (head != nullptr) // Make sure there are numbers in the list.
	{
		if (head->name == shipName)
		{
			currentShip = head;
			head = head->next;
			delete currentShip;
		}
		else
		{
			previousShip = currentShip = head;
			nextShip = head->next;
			while (currentShip != nullptr)
			{
				if (currentShip->name == shipName)
				{
					previousShip->next = nextShip;
					delete currentShip;
					success = true;
					break;
				}
				else
				{
					previousShip = currentShip;
					currentShip = currentShip->next;
					if (currentShip != nullptr)
						nextShip = currentShip->next;
				}
			}
			if (!success)
			{
				cout << "The ship was not found in the list." << endl;
			}
		}
	}
	else
	{
		cout << "The list is empty. :(" << endl;
	}
}


// RM, getCount implementation.
int starFleet::getCount()
{
	return shipCount;
}

[Hidden Squid]

lab5header.h

#include <iostream>
#include <algorithm>
#ifndef LAB4CLASS_H
#define LAB4CLASS_H
#include <cstring>


/*
THINGS THAT NEED TO BE DONE!!!!!!!

*Sort alphabetical order addShip, loadData.-----DONE

*Fix search

*Fix List all


*/
const int S_SIZE = 256;
const int FLEET_SIZE = 30;
using namespace std;

struct shipData
{
	char* name;
	int regNum;
	char* type;
	char* position;
	char* condition;
	char* captain;
	shipData * next; // can point to next ship
};

class starFleet
{
public:
	void addstarship(); // RM, changed name from addstarships to addstarship.
	void displayFleet();
	void loadData();    // RM, changed to void from int.
	void DeleteShip();
	bool searchFleet();
	int getCount();
	starFleet(); // Constructor
	~starFleet(); //deconstructor
	// Other methods go here.

private:
	int index;
	shipData * head; //Head of linked list
	int shipCount;
};
#endif 

[Hidden Squid]

lab5main.cpp

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstring>
#include "lab5header.h" 

using namespace std;
int main()
{
	starFleet myFleet;
	ofstream outputFile;
	ifstream inputFile;
	int count = 0;
	char choice;
	myFleet.loadData();
	inputFile.close();

	fstream file("starships.txt", fstream::app);
	do {
		cout << "\n**********************************" << endl;
		cout << "Welcome to ****'s star fleet manager" << endl;
		cout << "Here are your following options." << endl;
		cout << "a. Add a fleet" << endl;
		cout << "s. search for a fleet" << endl;				 /*Main Menu*/
		cout << "l. list all fleets" << endl;
		cout << "d. Delete a ship" << endl;
		cout << "q. To quit the fleet manager." << endl;
		cout << "Please use all lower case during the program" << endl;
		cout << "**********************************" << endl;
		cout << "please enter your choice: ";
		cin >> choice;
		cin.ignore(); // Added ignore, to get rid of '\n' stuck in the buffer.

		switch (choice) {
		case 'a':
		case 'A':
			if (myFleet.getCount() < FLEET_SIZE)
			{

				myFleet.addstarship();
				break;
			}
			else
				cout << "Sorry, no more room left in the system.";
			break;
		case 'd':
		case 'D':
		{
					myFleet.DeleteShip();
					break;
		}
		case 's':
		case 'S':
			if (myFleet.getCount() > 0)
			{
				myFleet.searchFleet();
				//class call bool search fleet
				break;
			}
			else
				cout << "sorry no Systems have been added in the database yet" << endl;
			break;
		case 'l':
		case 'L':
			myFleet.displayFleet();
			break;
		case 'q':
		case 'Q':
			cout << "Thank you for using ****'s Star Fleet manager." << endl;
			cout << "Endoy the rest of your day." << endl;
			file.close();
			myFleet.~starFleet();
			system("pause");
			return 0;
			break;
		}
	} while (choice != 'q');

	return 0;
}

[Hidden Squid]

Data file

Voyager;74656;Intrepid;Delta_Quadrant;Unknown;Janeway
moon_rocks;420;stoner;pluto;stoned;cap420
Grissom;638;Oberth;Genisis_Planet;Destroyed;Esteban
Enterprise;1701;Constitution;Klingon_Frontier;Operational;Kirk
beta;20;test;test;test;test
alpha;320;test;test;test;test

[JayhawkZombie]

Mkay.

Run this through your debugger. It will catch the exception on the line where the exception was thrown.

Tell us what line that error occurred on.

[Hidden Squid]

cout << "Name of the ship: " << cur->name << endl;

lab5class.cpp 225

runs through all of the ships and then once it runs out of ships to cout then it throws.

Unhandled exception at 0x00E69C82 in LAB5.exe: 0xC0000005: Access violation reading location 0xCDCDCDCD

[JayhawkZombie]

Sorry, this is gonna take some time.

I decided to slap this into my compiler.

I'm debugging currently. I can tell you that it happens because you're accessing memory you shouldn't be.

You should check for "inputFile.fail()" in your program. If it fails to open, your code will infinitely allocate memory until all the memory in RAM has been used up. It did that to me when I put the text file in the wrong place.

[Hidden Squid]

you're right i should do that. Ill add that in right now.

[JayhawkZombie]

Found it.
The issue is in loadData. When do you assign the last node's next pointer to be nullptr? Or rather, do you ever do this?

[Hidden Squid]

I see what you mean now. well looks like I dont ever assign nullptr anywhere. Let me see here hopefully I can figure this out.

[JayhawkZombie]

You assign everything to your temporary pointer, except 'next'. You can resolve it there.

[Hidden Squid]

I got it haha. Just really drained from finals week and this is the last thing i need to turn in i was just stumped. thank you again for all the help.

now to fix my deconstructor and I should be finished..

edit: well just fixed that should be good to go now.