Comparing stacks - c++

Question

I have a project to compare the contents of two stacks and I am having issues with this function. I believe I have the rest of the program done correctly. I am getting errors on B.myCharacters.empty() (Expression must have class type) and B==B.myCharacters (no operator "==" matched these operands).
bool CharStack::IsEqual(CharStack & B)
{
if (B.empty())
{
cout << "Stack is empty" << endl;
return false;
}
else if (B.myCharacters.empty())
{
cout << "Stack is empty" << endl;
return false;
}
else if (B == B.myCharacters)
return true;
}
Any help would be greatly appreciated.
Here is the header and driver. They were provided by the teacher for this project and I am not allowed to change them, even if there is a better way to do it.
#include <iostream>
#include <string>
using namespace std;
const int STACK_CAPACITY = 128;
typedef char StackElement;
class CharStack
{
private:
char myCharacters[STACK_CAPACITY]; // STL stack of chars.
int myTop;
public:
CharStack();
bool empty();
void push(const StackElement & value);
StackElement top() const;
void pop();
void StringToStack(const string & inStr);
friend ostream & operator <<(ostream & out, const CharStack & CS);
CharStack Reverse();
bool IsEqual(CharStack & B);
};
Driver
#include <string>
#include <cassert>
#include "Header.h"
using namespace std;
//introduces namespace std
int main(void)
{
ifstream in;
string fileName, line[30];
int i = 0;
CharStack N, M, P;
cout << "Enter file name for palindrome check: ";
cin >> fileName;
in.open(fileName.c_str());
assert(in.is_open());
while (!in.eof())
{
getline(in, line[i]);
N.StringToStack(line[i]);
cout << N << endl;
P = N;
M = N.Reverse();
if (P.IsEqual(M))
cout << "This line is a palindrome line" << endl;
else
cout << "This line is not a palindrome line" << endl;
i++;
}
cout << "\nProgram ended normally.\n";
system("pause");
}

Answer 1

Assuming your CharStack internally keeps the characters in a std::string, i.e.
class CharStack
{
std::string myCharacters; // internal data
public:
bool IsEqual(CharStack const&) const;
/* ... */
};
and IsEqual() should return if two stacks are identical, then the implementation is simply
bool CharStack::IsEqual(CharStack const&other) const
{
return myCharacters == other.myCharacters;
}
This compares an empty and a non-empty stack as not equal, but two empty stacks as equal, which arguably is the correct behaviour. If you want two empty stacks to be not equal you can
bool CharStack::IsEqualNonEmpty(CharStack const&other) const
{
return !myCharacters.empty() && myCharacters == other.myCharacters;
}
Note also the various uses of the keyword const.