C++ Visual Studio 2010, compile error C3867 when implementing dynamic stack - c++

Question

Currently working on an assignment for my datastructures class in university using stacks with dynamic memory allocation. Currently I'm getting a compile error C3867 saying I'm missing a function call from an argument list. I'm not really understanding where this error is coming from / I'm having trouble identifying what exactly is my error in my code; so I was wondering if someone might be kind enough to explain to me what it is, and maybe a friendly tip to remember so I can not have this happen again.
also, I apologize for the poor formatting, I've never posted here before sorry if its hard to read. :(
code posted below.
Thanks, and regards. :P
Header File:
#ifndef STACK_H
#define STACK_H
#include <iostream>
#include <iomanip>
struct Node
{
Node *nextPtr;
int value;
};
class Stack
{
public:
//Constructors and Deconstructers Here
Stack(); //Default Constructor
~Stack(); //Default Deconstructor
//logical methods || functions here
bool isEmpty(void); //prototype checks if stack is empty
//stack operations || function prototypes here
void push(int); //prototype to push values of type int onto the stack
int pop(); //prototype to pop values off of the stack and return a value
int top(); //prototype to return the top value
private:
Node *topPtr; //pointer to class Node Object, specifically for the top of the stack
};
#endif
Class File:
#include "CPTN278_A3_Stack_Arsenault.h"
using namespace std;
Stack::Stack()
{
topPtr = 0; //set the top pointer equal to zero.
}
Stack::~Stack()
{
while (!Stack::isEmpty())
{
Stack::pop();
}
}
bool Stack::isEmpty()
{
if(top == 0)
{
return true;
}
else
{
return false;
}
}
void Stack::push(int valueTMP)
{
Node *itemPtr = new Node;
itemPtr->nextPtr = topPtr;
itemPtr->value = valueTMP;
topPtr = itemPtr;
return;
}
int Stack::pop()
{
int returnValue; //unintialized int
Node *itemPtr; //unintialized pointer to node
returnValue = topPtr->value;
itemPtr = topPtr;
topPtr = itemPtr->nextPtr;
delete itemPtr;
return returnValue;
}
int Stack::top(void)
{
return topPtr->value; //**this is where my error is being thrown**
}

Answer 1

bool Stack::isEmpty()
{
if(top == 0) // <-- here is the problem
{
return true;
}
else
{
return false;
}
}
top is a function, to check its result you need top(). But I think you should be testing topPtr instead.

Answer 2

Before you had:
bool Stack::isEmpty()
{
if(top == 0) <-- top is a function, did you mean 'topPtr'?
{
return true;
}
else
{
return false;
}
}
Fix:
bool Stack::isEmpty()
{
return topPtr == 0;
}
That's your only build error. I'm not sure why you or the compiler thought it was in the top method. That's perfectly fine. Also there's no need to write:
if (expression_that_is_true_or_false)
return true;
else
return false;
Just do:
return expression_that_is_true_or_false;
I might be borderline preaching style here, but try to get used to understanding expressions this way. Expressions involving logical operators like ==, !=, &&, ||, <, >, etc. evaluate to true or false, so there is no need to do conditional branching only to then return what the expression originally evaluated to in the first place.
Oh and I realize this is homework, but check out std::stack later in your free time if you haven't already.

Answer 3

In function Stack::isEmpty(), something wrong with top.
bool Stack::isEmpty()
{
if(top == 0) // here
{
return true;
}
else
{
return false;
}
}
I think it should be as below:
if(topPtr==0)
...