Infix to Postfix

I'm trying to write a function that converts infix to postfix notation using stacks. My code compiles, but does not convert properly. Thanks in advance.

convertToPostfix is the function in question
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//Implementation File

#include <iostream>
#include <string>
#include "myStack.h"
#include "infixToPostfix.h"

using namespace std;

void infixToPostfix::convertToPostfix()
{	
	stackType<char> outputStack(50);
	stackType<char> operatorStack(50);
	char oper1, prevOper;
	char array[50], outArray[50];
	
	outputStack.initializeStack();
	operatorStack.initializeStack();
	pfx = "";
	strcpy(array,ifx.c_str());
	
	int sub = 0;

	while(array[sub] != '\0')
	{
		oper1 = array[sub];
		
		if(oper1 != ';')
		{
				//outputStack.push(oper1);
			//}
			if(oper1 != '(' && oper1 != ')' && oper1 != '*' && oper1 != '/' && oper1 != '+' && oper1 != '-')
			{
				outputStack.push(oper1);
			}
			else
			{
				if(operatorStack.isEmptyStack())
				{
					operatorStack.push(oper1);
					prevOper = oper1;
				
				}
				else
				{
					if(precedence(oper1, prevOper))
					{
						operatorStack.push(oper1);
					}
					else
					{
						outputStack.push(oper1);
					}
				}
			}
		}
		prevOper = oper1;
		sub++;
	}
	while(!operatorStack.isEmptyStack())
	{
		outputStack.push(operatorStack.top());
		operatorStack.pop();
		
	}
	int index = 0;
	while(!outputStack.isEmptyStack())
	{
		//cout << "while"<<outputStack.top() << endl;
		outArray[index] = outputStack.top();
		outputStack.pop();
		index++;
	}
	for(int maxElements = index - 1 ; outArray[maxElements] > 0; maxElements--)
	{	
		//cout << "this" << outArray[maxElements] << endl;
		pfx += outArray[maxElements];
		outArray[maxElements] = '\0';
	}
	
}//end convertToPostfix


bool infixToPostfix::precedence(char opr1, char opr2)
{
	int prec1, prec2;

	if (opr1 == '*' || opr1 =='/')
		prec1 = 2;
	else if(opr1 == '+' || opr1 == '-')
        prec1 = 1;
    else if(opr1 ='(')
        prec1 = 0;

    if (opr2 == '*' || opr2 == '/')
        prec2 = 2;
	else if(opr2 =='+' || opr2 == '-')
        prec2 = 1;

    return(prec1 >= prec2);
}//end precedence

void infixToPostfix::getInfix(string data)
{
    ifx = data;
    convertToPostfix();
}

void infixToPostfix::showInfix()
{
	cout << "Infix: " << ifx << endl;
}


void infixToPostfix::showPostfix()
{
	cout << "Postfix: " << pfx << endl;
}

infixToPostfix::infixToPostfix(string infx)
{
	ifx = infx;
	convertToPostfix();
}

This is the class I'm using
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//Header file: myStack.h

#ifndef H_StackType
#define H_StackType
 
#include <iostream>
#include <cassert>

#include "stackADT.h"

using namespace std;

//*************************************************************
// Author: D.S. Malik
//
// This class specifies the basic operation on a stack as an 
// array.
//*************************************************************

template <class Type>
class stackType: public stackADT<Type>
{
public:
    const stackType<Type>& operator=(const stackType<Type>&); 
      //Overload the assignment operator.

    void initializeStack();
      //Function to initialize the stack to an empty state.
      //Postcondition: stackTop = 0;

    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 true if the stack is full,
      //    otherwise returns false.

    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.


    stackType(int stackSize = 100); 
      //Constructor
      //Create an array of the size stackSize to hold 
      //the stack elements. The default stack size is 100.
      //Postcondition: The variable list contains the base address 
      //   of the array, stackTop = 0, and maxStackSize = stackSize

    stackType(const stackType<Type>& otherStack); 
      //Copy constructor

    ~stackType(); 
      //Destructor
      //Remove all the elements from the stack.
      //Postcondition: The array (list) holding the stack 
      //    elements is deleted.

private:
    int maxStackSize; //variable to store the maximum stack size
    int stackTop;     //variable to point to the top of the stack
    Type *list; //pointer to the array that holds the stack elements

    void copyStack(const stackType<Type>& otherStack); 
      //Function to make a copy of otherStack.
      //Postcondition: A copy of otherStack is created and assigned
      //    to this stack.
};

template <class Type>
void stackType<Type>::initializeStack()
{
    stackTop = 0;
}//end initializeStack

template <class Type>
bool stackType<Type>::isEmptyStack() const
{
    return(stackTop == 0);
}//end isEmptyStack

template <class Type>
bool stackType<Type>::isFullStack() const
{
    return(stackTop == maxStackSize);
} //end isFullStack

template <class Type>
void stackType<Type>::push(const Type& newItem)
{
    if (!isFullStack())
    {
        list[stackTop] = newItem;   //add newItem to the 
                                    //top of the stack
        stackTop++; //increment stackTop
    }
    else
        cout << "Cannot add to a full stack." << endl;
}//end push

template <class Type>
Type stackType<Type>::top() const
{
    assert(stackTop != 0);          //if stack is empty, 
                                    //terminate the program
    return list[stackTop - 1];      //return the element of the
                                    //stack indicated by 
                                    //stackTop - 1
}//end top

template <class Type>
void stackType<Type>::pop()
{
    if (!isEmptyStack())
        stackTop--;                 //decrement stackTop 
    else
        cout << "Cannot remove from an empty stack." << endl;
}//end pop

template <class Type>
stackType<Type>::stackType(int stackSize) 
{
    if (stackSize <= 0)
    {
        cout << "Size of the array to hold the stack must "
             << "be positive." << endl;
        cout << "Creating an array of size 100." << endl;

        maxStackSize = 100;
    }
    else
        maxStackSize = stackSize;   //set the stack size to 
                                    //the value specified by
                                    //the parameter stackSize

    stackTop = 0;                   //set stackTop to 0
    list = new Type[maxStackSize];  //create the array to
                                    //hold the stack elements
}//end constructor

template <class Type>
stackType<Type>::~stackType() //destructor
{
    delete [] list; //deallocate the memory occupied 
                    //by the array
}//end destructor

template <class Type>
void stackType<Type>::copyStack(const stackType<Type>& otherStack)
{ 
    delete [] list;				   
    maxStackSize = otherStack.maxStackSize;		   
    stackTop = otherStack.stackTop;			   
	  
    list = new Type[maxStackSize];		   			   

        //copy otherStack into this stack
    for (int j = 0; j < stackTop; j++)  
        list[j] = otherStack.list[j];
} //end copyStack

template <class Type>
stackType<Type>::stackType(const stackType<Type>& otherStack)
{
    list = NULL;

    copyStack(otherStack);
}//end copy constructor

template <class Type>
const stackType<Type>& stackType<Type>::operator=
   					(const stackType<Type>& otherStack)
{ 
    if (this != &otherStack) //avoid self-copy
        copyStack(otherStack);

    return *this; 
} //end operator=         
#endif 
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