linked list

[nikultimo]

hi everyone!
can someone help me with this program?
I have to make a linked list by reading a file. I have to read the command from the file and make an if else structure. If the command is "add"(this is the part I am having problems) I have to call a function that reads data in the file and adds those to the linked list. the "addOne" function is the one where the problem generates. Can you guys tell me what I am doing wrong?
This is the code:


#include <cstdlib>
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>

using namespace std;


struct webData
{
string domain;
string IPnumber;
};

typedef webData infoType ; // typedef on page 425 in Malik


struct nodeType
{
infoType info;
nodeType *link;
};


void print (nodeType *list);
nodeType * addOne ( nodeType * first, infoType newItem );


int main(int argc, char *argv[])
{
string filename;
ifstream inFile;
int count;
string command;
string newIP;


nodeType *webList, *temp,;
webData webInfo;


//Prompt the user for an input file
cout << "Enter the name of the input file: " ;
cin >> filename;

inFile.open(filename.c_str () );

if (!inFile)
{
cout << "\nInput file is missing! \n\n";
system ("pause");
return 1;
}

cout << filename << " was opened." << endl<<endl;


webList = NULL;


inFile >> command;


while ( command != "quit" )
{

if ( command == "display" )
{
print(webList);
}

///////////////////////////////////////////////////
else if (command == "add")
{
inFile >> webInfo.domain;
inFile >> webInfo.IPnumber;
webList = addOne ( webList, webInfo );
///////////////////////////////////////////////////

//count++;
}

/* else if ( command == "change" )
{
inFile >> webInfo.domain;
inFile >> newIP;

count++;
}

else if ( command == "eliminate" )
{
inFile >> webInfo.domain;

}
else if ( command == "search" )
{
inFile >> webInfo.domain;

count++;
} */


inFile >> command;
}







system("PAUSE");
return EXIT_SUCCESS;
}

///////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////

void print(nodeType *list)
{


nodeType *current;
current = list;


while (current != NULL)
{
cout << setw(30) <<left<< (current->info.domain);

cout <<setw(15)<<left << (current->info.IPnumber);

current = current->link;
cout << endl;
}
cout << endl;

}

//////////////////////////////////////////////////////////////////

nodeType * addOne ( nodeType * first, infoType newItem )
{

nodeType *newNode, *last;

last = NULL;

newNode = new nodeType;
newNode->info = newItem;
newNode->link = NULL;

if ( first == NULL ) //case 1: list is empty
{
first = newNode;
last = newNode;
}
else
{
newNode -> link = newNode;
last = newNode;

}

return first ;
}

////////////////////////////////////////////////////////////////


This is a part of the input file:

add www.spacebook.com 194.188.203.011
add www.myfacespace.org 191.198.103.223
add www.ratemystudent.com 192.168.251.244
add www.addtoothysmile.tv 191.168.312.112
display
quit

[D80DSL3A]

Is it just the addOne() you are having trouble with?
The local variable last serves no purpose. You could eliminate it.
This line:newNode -> link = newNode; points newNode to itself, creating a closed list with one node.
Are you trying to add a new node to the front of the list here?
If so, the following should work:

nodeType *newNode = new nodeType;
newNode->info = newItem;
newNode->link = first;// good for ALL cases
first = newNode;