writing my first oop code and having issues...

[arsonholiday]

My code has compiled, however when I am having trouble finding out why it is not working properly. It is supposed to display a menu (first displaying the contents of the list and whether or not it is sorted, then the menu). For some reason right off the bat it is saying the list is sorted when there is no list. Then when I enter one it will not display and still says it is sorted. I am having all kinds of trouble with this when I thought I had a pretty decent handle on it. Any help at all would be great. I guess I will just post the member functions I am having difficulty with, and if you need more to be able to help I will post it then.

Thanks!

  #include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
const int MLS = 50;
typedef int element;
const element SENTINEL = −1;

class AList{
  private:
      element items[MLS];
      int size;
      bool sorted;
  public:
      void Read ();
      void Print ();
      void BubbleSort ();
      void InsertionSort ();
      void Swap (int posa, int posb);
      void SelectionSort ();
      void LinearSearch (element target, bool &found, int &position);
      void BinarySearch (element target, bool &found, int &position);
      void GenerateRandomList ();
      element DisplayMenu ();
};


int main(){

AList B;
element selection;
element target;
bool found = false;
int position = 0;

selection = B.DisplayMenu ();
if (selection == 1)
  B.Read ();
else if (selection == 2)
  B.GenerateRandomList ();
else if (selection == 3)
  B.BubbleSort ();
else if (selection == 4)
  B.InsertionSort ();
else if (selection == 5)
  B.SelectionSort ();
else if (selection == 6)
  B.LinearSearch (target, found, position);
else if (selection == 7)
  B.BinarySearch (target, found, position);
else if (selection == 8){
  cout << "Quitting Sort and Search Demo Program, v1.0.";
  return 0;
  }
else {
  cout << "Not a menu option. Please select an option from the ";
  cout << "menu.";
  selection = B.DisplayMenu ();
  }
}

void AList::Read(){
//PRE: none
//POST: The N.O. AList is valid, filled with data entered by the user.

size = 0;
sorted = false;
element userval;

cout << "Enter elements, "<< SENTINEL <<" to stop: ";
userval = readElement();

while ((userval != SENTINEL) && (size < MLS)){
  items[size] = userval;
  size++;
    if (size < MLS)
       ;
    else
      cout << "This list is full." << endl;
      userval = readElement();
    }
main ();
}

element AList::DisplayMenu(){
//PRE: The list has been displayed and the sort status has been 
// displayed.
//POST: The menu has been displayed and the user has made a selection
// existing on the menu.

element selection;

cout << "List: " << endl;
if (size == 0)
  cout << "(empty)" << endl;
else
  Print ();

if (sorted == true)
  cout << "This list is sorted. " << endl;
else
  cout << "This list is not known to be sorted." << endl;

cout << "Enter a selection from the menu below." << endl;
cout << endl;
cout << "1. Reset the current list from the keyboard" << endl;
cout << "2. Reset the current list using randomly generated elements";
cout << endl;
cout << "3. Perform Bubble Sort on the current list" << endl;
cout << "4. Perform Insertion Sort on the current list" << endl;
cout << "5. Perform Selection Sort on the current list" << endl;
cout << "6. Perform Linear Search on the current list" << endl;
cout << "7. Perform Binary Search on the current list" << endl;
cout << "8. Quit the Program" << endl;
selection = readElement();
return selection;
}

void AList::Print(){
//PRE: The N.O. must be valid.
//POST: The elements in the object calling the method have been
// displayed.

for (int i = 0; i < size; i++)
  cout << items[i] << endl;
  cout << endl;
}

[ne555]

> if you need more to be able to help I will post it then.
http://www.eelis.net/iso-c++/testcase.xhtml (pay special attention to points 2 and 6)


Also, you cannot call your `main()' function from within your code.

[helios]

right off the bat it is saying the list is sorted when there is no list

Sounds correct. An empty list is sorted.
More to the point, though, you haven't defined a constructor for AList, so the values contained in the members immediately after construction are garbage.

Then when I enter one it will not display and still says it is sorted.

The problem is that you're calling main(). Think about what this does in terms of the program state. Which objects are created and used, etc.
Never call main(). It's not safe and there are no positive effects of doing it that can't be achieved by other means.