Using Own Stack Class in Encoding Program - Determine Size and Top

Question

I wrote a encoding program using the C++ stack library. Now I am trying to implement my own stack class, however I notice there are size() and top() member functions in the stack library. I am not sure how to implement my code without these functions, or how to write those functions in my class to get them to work properly with the code I already have.

Here is the areas that the stack library functions are being called in my readFileEncode(string filename, stack<char> &text, string cypher) function:

ifstream file(fileName, ios::in | ios::binary);
stack<char> temp;
char ch;

while (file.get(ch)){
    temp.push(ch ^ cypher[temp.size() % cypher.length()]);
}

while (!temp.isEmpty()){
    text.push(temp.top());
    temp.pop();
}

Here is my stack class:

#include<iostream>

#define TRUE 1
#define FALSE 0

template <class TYPE>

class stack{
struct node{
    TYPE element;
    node *next;
};

public:
node *top;
int stackSize;

stack(void);            //constructor
~stack(void);           //destructor free the stack

void push(TYPE & value);
TYPE pop(void);
TYPE peek(void);
int isEmpty(void);      //returns TRUE if empty
void print(void);
void reset(void);       //pop all the elements off the stack
size_t size(void) const;
TYPE topOf(void) const;
};

template <class TYPE>
stack<TYPE>::stack(void){
top = NULL;
stackSize = 0;
}

template <class TYPE>
stack<TYPE>::~stack(void){
cout << "Entering Stack Destructor" << endl;
reset();
cout << "Exiting Stack Destructor" << endl;
}

template <class TYPE>
void stack<TYPE>::push(TYPE & value){
node *temp = new node;

if (temp == NULL){
    cout << "Push: Memory Allocation Error" << endl;
    exit(1);
}

temp->element = value;
temp->next = top;
top = temp;
stackSize++;
}

template <class TYPE>
TYPE stack<TYPE>::pop(void){
TYPE returnElement;

if (top != NULL){
    node *temp = top;
    returnElement = top->element;
    top = top->next;
    delete temp;        //delete the node
    stackSize--;
}

return(returnElement);
}

template <class TYPE>
TYPE stack<TYPE>::peek(void){
TYPE returnElement;
if (top != NULL)
    returnElement = top->element;
cout << "Peek: " << returnElement << endl;
return(returnElement);
}

template <class TYPE>
int stack<TYPE>::isEmpty(void){
if (stackSize == 0)
    return(TRUE);
else
    return(FALSE);
}

template <class TYPE>
void stack<TYPE>::reset(void){
cout << "Reset Stack" << endl;
while (isEmpty() != TRUE){
    pop();
}
}

template <class TYPE>
void stack<TYPE>::print(void){
cout << "Inside Print Stack" << endl;
cout << "Stack size = " << stackSize << endl;

node * temp = top;
while (temp != NULL){
    cout << " " << temp->element << endl;
    temp = temp->next;
}
}

template <class TYPE>
size_t size(void) const{
return stackSize;
}

template <class TYPE>
TYPE stack<TYPE>::topOf(void) const{
return (*top).element;
}

This stack class is based on what I know of stack's. If there is anything wrong, it is because this is the first time I have written a stack class.

So basically, I am having problems either 1) writing the size() and top() functions, or 2) rewriting the while loops in my readFileEncode() function to use what I have. I had help properly writing the code to work with the stack library, but now trying to implement my own class is causing me problems. Any help would be appreciated.

EDIT 1: With the help of dyp, I changed the variable name of int size to int stackSize everywhere it appears in the class. Also, I change the function top() to topOf()

EDIT 2: Changed void push(TYPE &value) to void push(TYPE const& value) in all instances. Code is updated above. I used the following main() to test the class:

#include <iostream>
#include <cstdlib>
#include "stack.h"

using namespace std;

int main()
{
stack<int> s;
s.push(1);
s.push(2);
s.push(3);
s.push(4);
s.push(5);

cout << "size: " << s.size() << endl;
cout << "top element: " << s.topOf() << endl;

s.pop();
s.pop();

cout << "size: " << s.size() << endl;
cout << "top element: " << s.topOf() << endl;
cout << "empty: " << s.isEmpty() << endl;

s.pop();
s.pop();
s.pop();

cout << "size: " << s.size() << endl;
//cout << "top element: " << s.top() << endl;
cout << "empty: " << s.isEmpty() << endl;

system ("pause");
}

Everything worked fine, however when I attached the stack.h file to my encoding program, I get the following errors:

At file.put(text.top()); I get "term does not evaluate to a function taking 0 arguments," and the same error at text.push(temp.top());. I get the error, but not exactly sure how to fix it.

I also had to move public: in my class above node *top; int stackSize; because I got errors about them being private. This was not a problem with my test program. Not sure if that is ok either.

Answer 1

I used the following code to test my stack:

 int main()
{
stack<int> s;
s.push(1);
s.push(2);
s.push(3);
s.push(4);
s.push(5);

cout << "size: " << s.size() << endl;
cout << "top element: " << s.topOf() << endl;

s.pop();
s.pop();

cout << "size: " << s.size() << endl;
cout << "top element: " << s.topOf() << endl;
cout << "empty: " << s.isEmpty() << endl;

s.pop();
s.pop();
s.pop();

cout << "size: " << s.size() << endl;
//cout << "top element: " << s.top() << endl;
cout << "empty: " << s.isEmpty() << endl;

system ("pause");
}

I changed the code in my following stack class to the following and it seems to have worked:

void push(TYPE const& value);
size_t size(void) const;
TYPE topOf(void) const;

and:

void stack<TYPE>::push(TYPE const& value){
node *temp = new node;

if (temp == NULL){
    cout << "Push: Memory Allocation Error" << endl;
    exit(1);
}

temp->element = value;
temp->next = top;
top = temp;
stackSize++;
}

template <class TYPE>
size_t stack<TYPE>::size(void) const{
return stackSize;
}

template <class TYPE>
TYPE stack<TYPE>::topOf(void) const{
return (*top).element;
}

Also changed all occurrences of top() in my main to topOf(). Not sure if this is all proper, but it works, and I will take dyp's advice and turn it in at CodeReview.