Im having an issue with making a few test to overload the == operator in my linked list stack. i have the standard header files containing pop push and so forth. But Im having a problem writing these test. i was thinking maybe a test that would copy the stacks and see if each node is = to the other. Any help is appriciated Thank you.
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daviddoria 334
What do you mean by "tests"? Can you show us your current code? Can you tell us exactly what you are starting with and what you are wanting to produce?
David
Yes I do but I am currently At work. Once I get home I will post it with more information
rubberman 1,355
Ok. That would be helpful. Writing operators can sometimes be confusing for the new C++ developer. The signature is critical. If you are using a non-const signature and are (probably) applying it to a const object, reference, or pointer, then you will have a problem. Likewise, the arguments passed and the return value matter.
What it is i'm trying to do is overload the == operator. bool == operator (linkedStackType<Type>&);. I decided not to use const because things will be changing. My main problem is writing the function definition. What I need it to do is copy another stack then pop each off and compare each node. Unfortunately linked list are very hard for me, I am currently re-reading the linked list chapter to maybe see if that will help me. Any suggestions? Sorry about the long wait been really busy. HEre is the code I have :
//Header File: linkedStack.h
#ifndef H_StackType
#define H_StackType
#include <iostream>
#include <cassert>
#include "stackADT.h"
using namespace std;
//Definition of the node
template <class Type>
struct nodeType
{
Type info;
nodeType<Type> *link;
};
template <class Type>
class linkedStackType: public stackADT<Type>
{
public:
const linkedStackType<Type>& operator=
(const linkedStackType<Type>&);
//Overload the assignment operator.
bool isEmptyStack() const;
//Function to determine whether the stack is empty.
//Postcondition: Returns true if the stack is empty;
// otherwise returns false.
bool isFullStack() const;
//Function to determine whether the stack is full.
//Postcondition: Returns false.
void initializeStack();
//Function to initialize the stack to an empty state.
//Postcondition: The stack elements are removed;
// stackTop = NULL;
void push(const Type& newItem);
//Function to add newItem to the stack.
//Precondition: The stack exists and is not full.
//Postcondition: The stack is changed and newItem
// is added to the top of the stack.
Type top() const;
//Function to return the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: If the stack is empty, the program
// terminates; otherwise, the top
// element of the stack is returned.
void pop();
//Function to remove the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: The stack is changed and the top
// element is removed from the stack.
linkedStackType();
//Default constructor
//Postcondition: stackTop = NULL;
linkedStackType(const linkedStackType<Type>& otherStack);
//Copy constructor
~linkedStackType();
//Destructor
//Postcondition: All the elements of the stack are
// removed from the stack.
private:
nodeType<Type> *stackTop; //pointer to the stack
void copyStack(const linkedStackType<Type>& otherStack);
//Function to make a copy of otherStack.
//Postcondition: A copy of otherStack is created and
// assigned to this stack.
};
//Default constructor
template <class Type>
linkedStackType<Type>::linkedStackType()
{
stackTop = NULL;
}
template <class Type>
bool linkedStackType<Type>::isEmptyStack() const
{
return(stackTop == NULL);
} //end isEmptyStack
template <class Type>
bool linkedStackType<Type>:: isFullStack() const
{
return false;
} //end isFullStack
template <class Type>
void linkedStackType<Type>::initializeStack()
{
nodeType<Type> *temp; //pointer to delete the node
while (stackTop != NULL) //while there are elements in
//the stack
{
temp = stackTop; //set temp to point to the
//current node
stackTop = stackTop->link; //advance stackTop to the
//next node
delete temp; //deallocate memory occupied by temp
}
} //end initializeStack
template <class Type>
void linkedStackType<Type>::push(const Type& newElement)
{
nodeType<Type> *newNode; //pointer to create the new node
newNode = new nodeType<Type>; //create the node
newNode->info = newElement; //store newElement in the node
newNode->link = stackTop; //insert newNode before stackTop
stackTop = newNode; //set stackTop to point to the
//top node
} //end push
template <class Type>
Type linkedStackType<Type>::top() const
{
assert(stackTop != NULL); //if stack is empty,
//terminate the program
return stackTop->info; //return the top element
}//end top
template <class Type>
void linkedStackType<Type>::pop()
{
nodeType<Type> *temp; //pointer to deallocate memory
if (stackTop != NULL)
{
temp = stackTop; //set temp to point to the top node
stackTop = stackTop->link; //advance stackTop to the
//next node
delete temp; //delete the top node
}
else
cout << "Cannot remove from an empty stack." << endl;
}//end pop
template <class Type>
void linkedStackType<Type>::copyStack
(const linkedStackType<Type>& otherStack)
{
nodeType<Type> *newNode, *current, *last;
if (stackTop != NULL) //if stack is nonempty, make it empty
initializeStack();
if (otherStack.stackTop == NULL)
stackTop = NULL;
else
{
current = otherStack.stackTop; //set current to point
//to the stack to be copied
//copy the stackTop element of the stack
stackTop = new nodeType<Type>; //create the node
stackTop->info = current->info; //copy the info
stackTop->link = NULL; //set the link field of the
//node to NULL
last = stackTop; //set last to point to the node
current = current->link; //set current to point to
//the next node
//copy the remaining stack
while (current != NULL)
{
newNode = new nodeType<Type>;
newNode->info = current->info;
newNode->link = NULL;
last->link = newNode;
last = newNode;
current = current->link;
}//end while
}//end else
} //end copyStack
//copy constructor
template <class Type>
linkedStackType<Type>::linkedStackType(
const linkedStackType<Type>& otherStack)
{
stackTop = NULL;
copyStack(otherStack);
}//end copy constructor
//destructor
template <class Type>
linkedStackType<Type>::~linkedStackType()
{
initializeStack();
}//end destructor
//overloading the assignment operator
template <class Type>
const linkedStackType<Type>& linkedStackType<Type>::operator=
(const linkedStackType<Type>& otherStack)
{
if (this != &otherStack) //avoid self-copy
copyStack(otherStack);
return *this;
}//end operator=
#endif
//Header file: stackADT.h
#ifndef H_StackADT
#define H_StackADT
template <class Type>
class stackADT
{
public:
virtual void initializeStack() = 0;
//Method to initialize the stack to an empty state.
//Postcondition: Stack is empty
virtual bool isEmptyStack() const = 0;
//Function to determine whether the stack is empty.
//Postcondition: Returns true if the stack is empty,
// otherwise returns false.
virtual bool isFullStack() const = 0;
//Function to determine whether the stack is full.
//Postcondition: Returns true if the stack is full,
// otherwise returns false.
virtual void push(const Type& newItem) = 0;
//Function to add newItem to the stack.
//Precondition: The stack exists and is not full.
//Postcondition: The stack is changed and newItem
// is added to the top of the stack.
virtual Type top() const = 0;
//Function to return the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: If the stack is empty, the program
// terminates; otherwise, the top element
// of the stack is returned.
virtual void pop() = 0;
//Function to remove the top element of the stack.
//Precondition: The stack exists and is not empty.
//Postcondition: The stack is changed and the top
// element is removed from the stack.
};
#endif