Simple Linked List Error

This is a discussion on Simple Linked List Error within the C++ Programming forums, part of the General Programming Boards category; Whats up? I've been trying to teach my brother C++, however, in a recent "Linked List" application I coded, I've ...

  1. #1
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    Question Simple Linked List Error

    Whats up?

    I've been trying to teach my brother C++, however, in a recent "Linked List" application I coded, I've been getting errors (compiles fine, they're memory errors) with pointers.

    Here's my code:
    Code:
    #include <iostream>
    #include <string>
    #include <conio.h>
    
    using namespace std;
    
    class CEmployee
    {
    	public:
    
    		string name;
    		string position;
    		string phone;
    		
    		CEmployee * next;
    };
    
    
    void new_employee ( CEmployee * root, string name, string position, string phone )
    {
    	CEmployee * e;
    
    	e = root;
    
    	if ( root == NULL )
    	{
    		root = new CEmployee;
    		root->name = name;
    		root->position = position;
    		root->phone = phone;
    		root->next = NULL;
    	}
    	else
    	{
    		while ( e->next != NULL )
    			e = e->next;
    
    		e->next = new CEmployee;
    		e = e->next;
    		e->name = name;
    		e->position = position;
    		e->phone = phone;
    		e->next = NULL;
    	}
    }
    
    int main ( int argc, char * argv[] )
    {
    	CEmployee *root;
    	CEmployee *parse;
    	root = NULL;
    
    	string buffer[3];
    
    	char res = NULL;
    
    	do
    	{
    		cout << "Employee's Name: ";
    		getline ( cin, buffer[0] );
    
    		cout << "Employee's Position: ";
    		getline ( cin, buffer[1] );
    
    		cout << "Employee's Phone Number: ";
    		getline ( cin, buffer[2] );
    
    		new_employee ( root, buffer[0], buffer[1], buffer[2] );
    
    
    		cout << "Add another employee [Y/n]? " <<endl << endl;
    		res = toupper ( _getch() );
    	} while ( res == 'Y' );
    
    	system("cls");
    
    	cout << "List of employees: " << endl << endl;
    	parse = root;
    
    	while ( parse->next != NULL )
    	{
    		cout << "Details for " << parse->name << ":" << endl <<
    				"\tName: " << parse->name << endl <<
    				"\tPosition: " << parse->position << endl <<
    				"\tPhone: " << parse->phone << endl << endl;
    		parse = parse->next;
    	}
    
    	system("pause");
    	
    
    	return 0;
    }
    What happens is at the line "parse = root," windows tells me that the program has done something wrong and now it must be debugged. What have I done wrong in this program?

    Thanks in advance for any help,

    Guitarist809
    ~guitarist809~

  2. #2
    and the Hat of Guessing tabstop's Avatar
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  3. #3
    and the hat of wrongness Salem's Avatar
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    > new_employee ( root, buffer[0], buffer[1], buffer[2] );
    If you want the root = new ... inside the function to affect the variable in main, then you should pass a reference to it.

    Had you debugged your code, you would have seen it go through the if ( root == NULL ) on every iteration.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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