access violation segmentation fault raised in your program

Hi folks! I have written one program, which works ok, compiles etc. But I have one problem with it: when i am trying to debug it i am getting the following error: "access violation segmentation fault raised in your program", it just pops up as a window and i can't even debug my program at all. I am using devc++ with it.If any one know how to fix this stupid proble, please reply asap.Any help is appreciated.Thanks.
Heres the code:

Code:

---

#include<iostream>
#include<iomanip>
#include<conio.h>

using namespace std;

const int MAX = 10;

class LinearQueue
{
      private:
          int queue[MAX];
          int rear;
          int front;

      public:
          //LinearQueue();

      void Queue();   
          void Delete();
          void Insert();
          void print_queue();
          void show_working();
};

void LinearQueue::Queue()
{
        rear=-1;
        front=-1;

        for(int count=0;count < MAX;count++)
            queue[count]=0;
}

void LinearQueue::Insert()
{
int item;

        cout << setw(40) <<  "\n\n\n\n\n\t Enter value to insert into the Queue : " << endl << endl;
        cin >> item;

if(rear == (MAX-1))
            cout << "\n\n\t ***  Error : Queue is full. \n" << endl;

else if(rear==-1 && front==-1)
          {
            rear++;
            queue[rear]=item;
            front=rear;

            cout << "\n\n\t *** " << item << " is inserted into the Queue." << endl;
          }
else
          {
            rear++;
            queue[rear]=item;

            cout << "\n\n\t *** " << item << " is inserted into the Queue." << endl;
      }
        cout << "\n\n\n\t\t Press any key to return to Menu " << endl;
     
        cin.get();
     
}

void LinearQueue::Delete()
{
if(rear==-1 && front==-1)
            cout << "\n\n\n\t ***  Error : Queue is empty. \n" << endl;

else
          {
            cout << "\n\n\n\t *** " << queue[front] << " is deleted from the Queue." << endl;

            queue[front]=0;

if(front==rear)
                front=rear=-1;

else
                front++;
          }

        cout << "\n\n\n\t\t Press any key to return to Menu. " << endl;

        cin.get();
}

void LinearQueue::print_queue()
{
if(front!=-1 && rear!=-1)
          {
            cout << "\n\n\n\n\n\t Values inserted into the Queue are : \n" << endl;

for(int count=front;count<=rear;count++)
                cout << "\t Stack [" << count << "]  =  " << queue[count] << endl;
          }

else
            cout << "\n\n\n\n\n\t *** Nothing to show. " << endl;

        cout << "\n\n\n\t\t Press any key to return to Menu. " << endl;

        cin.get();
}

void LinearQueue::show_working()
{
char Key;

do
          {
            system("CLS");

        cout << setw(40) << "                      " << endl;
       
            cout << setw(53) <<  "***Linear ***** MAIN MENU ***** Queue*** " << endl;

        cout << setw(40) << "                      " << endl;
       
            cout << setw(49) << "Select one of the listed operation : " << endl;
            cout << setw(42) << "Press 'I' to Insert a value : " << endl;
            cout << setw(42) << "Press 'D' to Delete a value : " << endl;
            cout << setw(44) << "Press 'P' to Print the values : " << endl;
            cout << setw(31) << "Press 'E' to Exit: " << endl;
            Input:
            cout << setw(40) << "                      " << endl;
            cout << setw(39) << "Please Enter Your Choice : " << endl;

            Key = cin.get();

if(int(Key)==27 || Key=='e' || Key=='E')
break;

else if(Key=='i' || Key=='I')
                Insert( );

else if(Key=='d' || Key=='D')
                Delete( );

else if(Key=='p' || Key=='P')
                print_queue();

else
goto Input;
          }
while(1);
}


int main()
{
      LinearQueue obj;

      obj.show_working();

return 0;
}

---

Surely you can use another do while for your loop instead of using goto?

I also fail to see the purpose of this line:

Code:

---

        cout << setw(40) << "                      " << endl;

---

Wouldn't

Code:

---

        cout << endl;

---

do quite the same thing?

Code:

---

if(int(Key)==27 || Key=='e' || Key=='E')

---

is the same as

Code:

---

if(Key==27 || Key=='e' || Key=='E')

---

so why do you have a cast? [Any chance you've been programming Basic before?]

Sorry, can't say where you are do get things wrong in the Insert function - I've got a train to catch.

--
Mats

Thanks! I did basic C++ 2 years ago. Those lines of code that you have highlighted are not causing the problem, but thanks anyway. When i am trying to debug it gives me the message and it is said that error is in the following piece of code:

Code:

---

void LinearQueue::Insert()
{
int item;

        cout << setw(40) <<  "\n\n\n\n\n\t Enter value to insert into the Queue : " << endl << endl;
        cin >> item;

if(rear == (MAX-1))
            cout << "\n\n\t ***  Error : Queue is full. \n" << endl;

else if(rear==-1 && front==-1)
          {
            rear++;
            queue[rear]=item;
            front=rear;

            cout << "\n\n\t *** " << item << " is inserted into the Queue." << endl;
          }
else
          {
            rear++;
            queue[rear]=item; ///*** this is the line that causes the problem***

            cout << "\n\n\t *** " << item << " is inserted into the Queue." << endl;
      }
        cout << "\n\n\n\t\t Press any key to return to Menu " << endl;
     
        cin.get();
     
}

---

Does your class have a constructor that gives rear and front an initial value of -1? I don't think so...

Quote:

---

Originally Posted by anon

Does your class have a constructor that gives rear and front an initial value of -1? I don't think so...

---

I think i doesn't , can you tell me please what kind of construct should it be and where should i put it in the code?Thanks

Code:

---

      public:
          //LinearQueue();

---

This is the correct declaration of a default constructor.

Code:

---

void LinearQueue::Queue()
{
        rear=-1;
        front=-1;

        for(int count=0;count < MAX;count++)
            queue[count]=0;
}

---

I suppose this was supposed to be the implementation. However, constructors don't have return type and the name is the same as the name of the class:

Code:

---

LinearQueue::LinearQueue()
{
    ...
}

---

Quote:

---

Originally Posted by anon

Code:

---

      public:
          //LinearQueue();

---

This is the correct declaration of a default constructor.

Code:

---

void LinearQueue::Queue()
{
        rear=-1;
        front=-1;

        for(int count=0;count < MAX;count++)
            queue[count]=0;
}

---

I suppose this was supposed to be the implementation. However, constructors don't have return type and the name is the same as the name of the class:

Code:

---

LinearQueue::LinearQueue()
{
    ...
}

---

---

I have changed my code as you have posted:
now i have:
[QUOTE=anon;857312]

Code:

---

      public:
          LinearQueue();

---

Code:

---

void LinearQueue::LinearQueue()
{
        rear=-1;
        front=-1;

        for(int count=0;count < MAX;count++)
            queue[count]=0;
}

---

but I am geting another error "return type specification for constructor invalid"
and now program doesn't compile. If you want you can copy and paste the code and try to run it yourself, and you'll see what type of errors come up then.

remove "void" from that, and you'd be good to go.

--
Mats

Thanks for your help everyone!