balancedparantheses

I dont no how to fix. Can someone help me out plz. (Please see the picture)
[IMG]http://i61.tinypic.com/2r2cfnq.png[/IMG]

#ifndef DYNINTSTACK_H
#define DYNINTSTACK_H

class DynIntStack
{
private:
    // Structure for stack nodes
    struct StackNode
    {
        int value;        // Value in the node
        StackNode *next;  // Pointer to the next node
    };

    StackNode *top;      // Pointer to the stack top

public:
    // Constructor
    DynIntStack()
    {  top = NULL; }

    // Destructor
    ~DynIntStack();

    // Stack operations
    void push(int);
    void pop(int &);
    bool bracketsame(char,char);
    bool balancedparantheses(string); //checks if parentheses are
    bool isEmpty();
};
#endif




#include "DynIntStack.h"
#include <iostream>
#include <string>
using namespace std;

// Main to run program
int main()
{
    string expression;

    cout<<"Enter an expression to check: ";
    cin>>expression;

    if(DynIntStack::balancedparantheses(expression))
        cout<<"Balanced expression \n";

    else
        cout<<"Expression is not balanced \n";
}
bool bracketsame(char opening,char closing) // function checks if opening and closing brackets are same
{
    if(opening == '(' && closing == ')') return true;
    else if(opening == '{' && closing == '}') return true;
    else if(opening == '[' && closing == ']') return true;
    return false;
}
bool balancedparantheses(string exp) //checks if parentheses are
{                                    //balanced or not
    stack<char> StackNode;
    for(int i =0;i<exp.length();i++)
    {
        if(exp[i] == '(' || exp[i] == '{' || exp[i] == '[')
            StackNode.push(exp[i]);
        else if(exp[i] == ')' || exp[i] == '}' || exp[i] == ']')
        {
            if(StackNode.empty() || !bracketsame(StackNode.top(),exp[i]))
                return false;
            else
                StackNode.pop();
        }
    }
    return StackNode.empty() ? true:false;
}