CODEWITHSUNDEEP
c++linked-list
user1276137
user1276137

Reputation: 1

Simple Linked list to read in integers and display them back C++

I'm getting errors trying to compile my prog program in my header file and I cant figure them out.

This is a simple linked list program to user input a list of integers and display them back. I will appreciate all the help.

Heres is my header file code

#ifndef Linklist
#define Linklist
#include<cstdlib>


class linked_list {



public:

linked_list() {head = NULL; tail = NULL;}

void insert_front (int num);
bool empty() {return (head == NULL);}

private:

node *head;
node *tail;


};

Below are the errors im getting

1>Compiling...
1>Linklist.cpp

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(19) : error C2143: syntax error : missing ';' before '*'

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(19) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(19) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(20) : error C2143: syntax error : missing ';' before '*'

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(20) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(20) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(12) : error C2065: 'head' : undeclared identifier

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(12) : error C2065: 'tail' : undeclared identifier

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(15) : error C2065: 'head' : undeclared identifier

1>c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h(27) : fatal error C1070: mismatched #if/#endif pair in file 'c:\users\albert\documents\visual studio 2008\projects\linklist\linklist\linklist.h'

1>Build log was saved at "file://c:\Users\albert\Documents\Visual Studio 2008\Projects\Linklist\Linklist\Debug\BuildLog.htm"

1>Linklist - 10 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Here is my program implementation

#include "linklist.h"
#include <iostream>
using namespace std;


int main()
{



void linked_list::insert_front (int num) {

node *head;
      node *tail;
      node *p;
      int num;

      head = NULL;
      tail = NULL;

 node *p = new node;
 p->set_data ( num):
 p->set_next ( head);
 head = p;

   for (int i=0; i<3; i++)
    {
       cout << "Enter number :";
       cin >> num;
       newNode = new nodeType;         // Create the new node
       newNode->data = num;            // and assign its data value
       newNode->link = NULL;           // make its link point to nothing

       if (first == NULL)              // If there is nothing in the list, then make the 
        {                               
           first = newNode;            // newNode the first item and the last item
            last = newNode;
        }

       else                            // Else if first already has a value
        {                               
           last->link = newNode;     // make the last item link to the newNode
           last = newNode;           // and make newNode the last item

        }
   }

    // Display the list

    DisplayList(first);
    system("PAUSE");
    return(0);


}

Upvotes: 0

Views: 2054

Answers (5)

thb
thb

Reputation: 14434

The type node is not in scope.

You probably need a new header file node.h to define the missing type, if the type will elsewhere be used. Otherwise, you should at least define it at the top of the file you have listed.

Of greater concern is that you do not understand the importance of proper indentation of code. Until you do, problems like this will plague you.

Upvotes: 0

111111
111111

Reputation: 16148

If this isn't some sort of homework assignment then please consider using std::list

#include <vector>
#include <iostream>
#include <iterator>
#include <algorithm>

int main()
{
    std::cout << "Enter ints end with q" << std::endl;
    std::list<int> l; //a deque is probably better TBH
    std::copy(std::istream_iterator<int>(std::cin),
              std::istream_iterator<int>(),
              std::inserter<int>(l, l.begin()));

    std::copy(l.begin(), l.end(),
              std::ostream_iterator<int>(std::cout, " "));
}

Rewriting existing containers is just a bad idea; also in this use case a deque is better than a list.

Upvotes: 1

rahul
rahul

Reputation: 6487

I never worked on VC++... but try declaring the private section in the header file before the public section... And is node a built in data type in VC++?

Upvotes: 0

Some programmer dude
Some programmer dude

Reputation: 409136

Do you define the node class anywhere? You need to include the file it's in in the header file as well, or at least define it:

class node;

class linked_list { ... };

Also, don't forget the #endif at the end of the header file!

Upvotes: 1

Carl Norum
Carl Norum

Reputation: 224844

You're using some type node all over the place, but it isn't defined anywhere in your program. You're going to need to do that.

In addition there is some funny business going on with nested functions in main(). I don't know if you meant to do that or not, but it's certainly strange.

Upvotes: 2

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