help me with this single linked list

what is wrong with my code?i cant figure it out.

#include<iostream.h>
#include<stdlib.h>
#include<stdio.h>


#define MAX 50

struct Node
{
	char judul[MAX];
	char pengarang[MAX];
	int harga;
	Node* nextPtr;
};


Node* makeNode(char judul[], char pengarang[], int harga)
{
	Node* newNodePtr = (Node*)malloc(sizeof(Node));
	if(newNodePtr == NULL)
	{
		cout << "Out of Memory" << endl;
		exit(1);
	}
	else
	{
		newNodePtr->judul = judul;		
		newNodePtr->pengarang = pengarang;	
		newNodePtr->harga = harga;
		newNodePtr->nextPtr = NULL;
	}
	return newNodePtr;
}

void insertNode(char judul[],char pengarang[],int harga)
{

	Node* headPtr = NULL;
	Node* rearPtr = NULL;
	Node* newNodePtr = NULL;
	Node* myPtr = NULL;
	Node* newPtr = NULL;
	Node* prevPtr = NULL;

	
				if(headPtr == NULL)
				{
					headPtr= makeNode(judul,pengarang,harga);
					
					rearPtr = headPtr;
					myPtr = headPtr;

				
				}
				else if(judul <= headPtr->judul && pengarang <= headPtr->pengarang)	
				{
						myPtr = headPtr;
						headPtr = makeNode(judul,pengarang,harga);
						
						headPtr->nextPtr = myPtr;

					
				}
				
				else if(judul >= rearPtr->judul && pengarang >= rearPtr->pengarang)		
				{
					myPtr = rearPtr;
					rearPtr = makeNode(judul,pengarang,harga);
					
					myPtr->nextPtr = rearPtr;

				
				}				
				else
				{					
					newPtr = makeNode(judul,pengarang,harga);
					
					myPtr = headPtr;
					while(judul >= myPtr->judul)		
					{
						prevPtr = myPtr;
						myPtr = myPtr->nextPtr;
					}
					prevPtr->nextPtr = newPtr;
					newPtr->nextPtr = myPtr;
																
				}
}

void deleteNode(char judul[])
{
	Node* headPtr = NULL;
	Node* rearPtr = NULL;
	Node* newNodePtr = NULL;
	Node* myPtr = NULL;
	Node* newPtr = NULL;
	Node* prevPtr = NULL;
			
			if(headPtr->judul == judul)			
			{
				myPtr=headPtr;
				headPtr=headPtr->nextPtr;
				cout << "Data " << judul << " telah dihapus" << endl;
				free(myPtr);
			}


			else
			{
				myPtr = headPtr->nextPtr;
				prevPtr = headPtr;
				while(myPtr != NULL && myPtr->judul != judul)  //?
				{
					myPtr=myPtr->nextPtr;
					prevPtr=prevPtr->nextPtr;
				}
				if(myPtr==NULL)
				{
					cout << "Element not found" << endl << endl;
				}
				else
				{
					prevPtr->nextPtr=myPtr->nextPtr;
					cout << "Data " << judul << " telah dihapus" << endl;
					free(myPtr);
				}
				

			}

		

}

void display()
{
	Node* headPtr = NULL;
	Node* rearPtr = NULL;
	Node* newNodePtr = NULL;
	Node* myPtr = NULL;
	Node* newPtr = NULL;
	Node* prevPtr = NULL;

			cout << endl << endl;
			cout << "Data Anda: " << endl;
			cout << "Judul" << "\t" << "Pengarang" << "\t" << "Harga" << endl ;
			myPtr = headPtr;
			while (myPtr != NULL)
			{
					cout << "  " << myPtr->judul << "\t" ;
					cout << "    " << myPtr->pengarang << "\t" ;
					cout << "\t" << myPtr->harga  ;
					myPtr = myPtr->nextPtr;
					cout << endl;
			}
			cout << endl;
}


void main()
{
	char judul[MAX];
	char pengarang[MAX];
	int harga;
	int choice ;
	

	while(choice != 0)
	{
		cout << "Insert your choice : " << endl;
		cout << "(1) Insert "  << "\t" << " (3) Display " << endl;
		cout << "(2) Delete "  << "\t" << " (0) Exit " << endl;
	
		cout << "Your choice : ";
		cin >> choice;
		cout << endl;

		if(choice == 1)		//insert
		{
			cout << "Masukkan Judul : ";
			cin >> judul;		
			cout << "Masukkan Nama Pengarang : ";
			cin >> pengarang;
			cout << "Masukkan Harga : ";
			cin >> harga;
			insertNode(judul,pengarang,harga);
			display();
		}
						
		if(choice == 2)		//delete
		{
			cout << "Delete Data : ";
			cin >> judul;

			deleteNode(judul);
			display();
		}
		if(choice == 3)   //display
		{
			display();
		}
		if(choice == 4)   //Exit
		{
			cout << "Thank You" << endl;
		}
	}
	
	
}

i want to type in more than 1 char. but i can't find the way to solve it.
fyi, i'm using visual studio C++ 6 :)
thanks, any helps will be appreciated

anitaNg

Newbie Poster

6 posts since May 2011

Reputation Points: 10

Solved Threads: 0

1 Year Ago

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Line 28:

newNodePtr->pengarang = pengarang;

You are only copying the pointer over, not the contents of the string. Use strcpy(newNodePtr->pengarang,pengarang); instead (or better, since you don't know how large your source string is, use strncpy ).

jonsca

Quantitative Phrenologist

Team Colleague

5,621 posts since Sep 2009

Reputation Points: 1,165

Solved Threads: 581

1 Year Ago

wow thanks. it helped so much. :)
but there's one problem. the data didn't sort alphabetically as it used to be. any idea?

anitaNg

Newbie Poster

6 posts since May 2011

Reputation Points: 10

Solved Threads: 0

1 Year Ago

Show Comments

You reset head pointer to null on line 38. Why? It's guaranteed to follow the path of that first if statement each time, and what if there already is a valid head pointer? (hint pass it into your function) That may not be the problem, but it's one of the first places I would look.

jonsca

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1 Year Ago

oh yeah i didn't realize about that, thanks! :)
but still. it didn't sort and the delete function seems not to work.

anitaNg

Newbie Poster

6 posts since May 2011

Reputation Points: 10

Solved Threads: 0

1 Year Ago

If you don't rework insertNode() like I was saying, of course it's not going to sort. Get the insert procedure correct and the deleting will be trivial. Do you have access to a debugger? (I don't remember how good the one was in VC6). You need to step through your code and watch as the nodes are added. I've given you a pointer, but I'm not going to rewrite it for you. Take another crack at it and post back your new insertNode() function.

jonsca

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5,621 posts since Sep 2009

Reputation Points: 1,165

Solved Threads: 581

1 Year Ago

okay i have changed the insertNode() and deleteNode()and overall it seems to workout,thanks to you :) but there's one more problem. when i debug it, and input more than 4 times, the program stops. any idea?

btw, here are the program

#include<iostream.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>



#define MAX 50

struct Node
{
	char judul[MAX];
	char pengarang[MAX];
	int harga;
	Node* nextPtr;
};

	Node* headPtr = NULL;
	Node* rearPtr = NULL;
	Node* newNodePtr = NULL;
	Node* myPtr = NULL;
	Node* newPtr = NULL;
	Node* prevPtr = NULL;

Node* makeNode(char judul[], char pengarang[], int harga)
{
	Node* newNodePtr = (Node*)malloc(sizeof(Node));
	if(newNodePtr == NULL)
	{
		cout << "Out of Memory" << endl;
		exit(1);
	}
	else
	{
		strcpy(newNodePtr->judul,judul);		
		strcpy(newNodePtr->pengarang,pengarang);	
		newNodePtr->harga = harga;
		newNodePtr->nextPtr = NULL;
	}
	return newNodePtr;
}

void insertNode(char judul[],char pengarang[],int harga)
{

				if(headPtr == NULL)
				{
					headPtr= makeNode(judul,pengarang,harga);		
					rearPtr = headPtr;
					myPtr = headPtr;
				
				}
				else if(strcmp(judul,headPtr->judul)<=0)	
				{
						myPtr = headPtr;
						headPtr = makeNode(judul,pengarang,harga);						
						headPtr->nextPtr = myPtr;
					
				}
				
				else if(strcmp(judul,rearPtr->judul)>=0)		
				{
					myPtr = rearPtr;
					rearPtr = makeNode(judul,pengarang,harga);				
					myPtr->nextPtr = rearPtr;				
				}				
				else
				{					
					newPtr = makeNode(judul,pengarang,harga);
					
					myPtr = headPtr;
					while(judul >= myPtr->judul)		
					{
						prevPtr = myPtr;
						myPtr = myPtr->nextPtr;
					}
					prevPtr->nextPtr = newPtr;
					newPtr->nextPtr = myPtr;																
				}

				cout << endl << endl;
				//display
				cout << "Data Anda: " << endl;
				cout << "Judul" << "\t" << "Pengarang" << "\t" << "Harga" << endl ;
				myPtr = headPtr;
				while (myPtr != NULL)
				{
						cout << "  " << myPtr->judul << "\t" ;
						cout << "    " << myPtr->pengarang << "\t" ;
						cout << "\t" << myPtr->harga  ;
						myPtr = myPtr->nextPtr;
						cout << endl;
				}
				cout << endl;
}

void deleteNode(char judul[])
{
	
			
			if(strcmp(headPtr->judul,judul)==0)			
			{
				myPtr=headPtr;
				headPtr=headPtr->nextPtr;
				cout << "Data " << judul << " telah dihapus" << endl;
				free(myPtr);
			}


			else
			{
				myPtr = headPtr->nextPtr;
				prevPtr = headPtr;
				while(myPtr != NULL && myPtr->judul != judul)  //?
				{
					myPtr=myPtr->nextPtr;
					prevPtr=prevPtr->nextPtr;
				}
				if(myPtr==NULL)
				{
					cout << "Element not found" << endl << endl;
				}
				else
				{
					prevPtr->nextPtr=myPtr->nextPtr;
					cout << "Data " << judul << " telah dihapus" << endl;
					free(myPtr);
				}
				

			}
			//display
			cout << endl << endl;
			cout << "Data Anda: " << endl;
			cout << "Judul" << "\t" << "Pengarang" << "\t" << "Harga" << endl ;
			myPtr = headPtr;
			while (myPtr != NULL)
			{
					cout << "  " << myPtr->judul << "\t" ;
					cout << "    " << myPtr->pengarang << "\t" ;
					cout << "\t" << myPtr->harga  ;
					myPtr = myPtr->nextPtr;
					cout << endl;
			}
			cout << endl;

		

}




void main()
{
	char judul[MAX];
	char pengarang[MAX];
	int harga;
	int choice ;
	

	while(choice != 0)
	{
		cout << "Insert your choice : " << endl;
		cout << "(1) Insert "  << "\t" << " (3) Display " << endl;
		cout << "(2) Delete "  << "\t" << " (0) Exit " << endl;
	
		cout << "Your choice : ";
		cin >> choice;
		cout << endl;

		if(choice == 1)		//insert
		{
			cout << "Masukkan Judul : ";
			cin >> judul;		
			cout << "Masukkan Nama Pengarang : ";
			cin >> pengarang;
			cout << "Masukkan Harga : ";
			cin >> harga;
			insertNode(judul,pengarang,harga);
			
		}
						
		if(choice == 2)		//delete
		{
			cout << "Delete Data : ";
			cin >> judul;

			deleteNode(judul);
			
		}
		if(choice == 3)   //display
		{

			cout << endl << endl;
			cout << "Data Anda: " << endl;
			cout << "Judul" << "\t" << "Pengarang" << "\t" << "Harga" << endl ;
			myPtr = headPtr;
			while (myPtr != NULL)
			{
					cout << "  " << myPtr->judul << "\t" ;
					cout << "    " << myPtr->pengarang << "\t" ;
					cout << "\t" << myPtr->harga  ;
					myPtr = myPtr->nextPtr;
					cout << endl;
			}
			cout << endl;
		}
		if(choice == 4)   //Exit
		{
			cout << "Thank You" << endl;
		}
	}
	
	
}

anitaNg

Newbie Poster

6 posts since May 2011

Reputation Points: 10

Solved Threads: 0

1 Year Ago

hey Jonsca, i think i figured it out already. thanks for helping me! :) i really appreciate it :)

anitaNg

Newbie Poster

6 posts since May 2011

Reputation Points: 10

Solved Threads: 0