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-   -   linked stack output problems (http://www.go4expert.com/forums/linked-stack-output-t15694/)

xenoglaux 1Jan2009 17:02

linked stack output problems
 
here is the code
Code:

#include <iostream.h>
#include<stdlib.h>
#include<conio.h>
struct node
{   
int data;
    struct node *link;
 };
 struct node *top=NULL,*temp;
 void main()
 {    int choice,data;
   
          while(1)//infinite loop is used to insert/delete infinite number of nodes   
    {                cout << "\n1.Push\n2.Pop\n3.Display\n4.Exit\n";       
    cout << "\nEnter ur choice:";       
    cin >> choice;       
    switch(choice)       
{  case 1:
  temp=(struct node *)malloc(sizeof(struct node));
  cout << "Enter a node data :";
  cin >> data;
  temp->data=data;
  temp->link=top;
  top=temp; 
                   
break; 
               
 case 2:   
  if(top!=NULL)         
  { 
               
    cout << "The poped element is " << data,top->data;
 
      top=top->link;           
  }         
      else         
    {        cout << "\nStack Underflow";                } 
            break; 
                     
 case 3:
          temp=top; 
    if(temp==NULL)     
 {        cout << "\nStack is empty\n";  } 
      while(temp!=NULL) 
 {             
    cout << "->" <<data << "->",temp->data;
                temp=temp->link;            } 
          break;
         
 case 4:     
 
  exit(0);        }         
     
  } 
    }

here's the problem
when i push a number say...
2 4 5 6
the display result is 6->6->6->6->
when i choose pop options the result is
The popped element is 6
and i press 2 again to pop out
The popped element is 6 (again)

is there any mistaken in my code? :crazy:
Thanks before

skp819 2Jan2009 13:52

Re: linked stack output problems
 
I am not sure but I think display should writer as below:
Code:

case 3:
          temp=top; 
    if(temp->link!=NULL)     
 {        cout << "\nStack is empty\n";  } 
      while(temp!=NULL) 
 {             
    cout <<temp->data<<"->";
                temp=temp->link;         
 } 
          break;


xpi0t0s 4Jan2009 17:21

Re: linked stack output problems
 
Is the output really 6->6->6->6->, or is it ->6->->6->->6->->6-> ? Make sure you state EXACTLY the output from the program (for example, you've changed "poped" to "popped", so clearly either you haven't given the output from the program or you've changed the code since posting it).

cout << "->" <<data << "->",temp->data;

Interesting use of the comma operator. Maybe have another look at this line?

Edit: oh yeah, and you've got a memory leak in case 2.

skp819 5Jan2009 10:47

Re: linked stack output problems
 
Here I am posting stack programming singly link list.
From here you can learn it. It will help you to find your mistake in your programe.

Code:

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

class link_stack
   
{

    struct node
   
    {

        int id;

        char name[10];

        node *next;

    };

    node *top,*x,*ptr;

    public:

        link_stack()

        {

            top=x=ptr=NULL;

        }

        void push()

        {

            x=new node;

            cout << "Enter an ID number and name: ";

            cin >> x->id >> x->name;


            x->next=top;

            top=x;

        }

        int pop(char n[])

                {    int result;

                        if(top==NULL)

                                cout<<"\nStack is Empty";

                        else

                        {    result = top->id;
                               
                                strcpy(n, top->name);

                                x=top;

                                top=top->next;

                                delete x;

                                return result;

                        }

                }

        void empty()
{

                char name[10];
                           
                        while(!obj.empty())
                                       
                        {

                                cout << pop(name) << ": " << name << endl;

                          }

                }
           
};

void main()

{

    link_stack obj;

    int choice;

    do

    {

        cout << "\n ----------MENU---------- \n";

        cout << "1.Push\n"
           
                        <<  "2.Pop\n"
             
                        <<  "3.Exit";

                cout << "\nEnter your choice: ";

        cin>>choice;

        switch(choice)

        {

        case 1: obj.push();

            break;

        case 2: obj.pop();

        obj.empty();

            break;

        case 3: cout << endl;

        }

    }

    while (choice!=3);

    getch();

}



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