Why is my Pre to Postfix code not working?

Question

For a class assignment, I have to use two stacks in C++ to make an equation to be converted to its left to right equivalent: 2+4*(3+4*8) --> 35*4+2 --> 142

Here is the main code:

#include <iostream>
#include <cstring>
#include "ctStack.h"

using namespace std;

int main (int argc, char * const argv[]) {
 string expression = "2+4*2";
    ctstack *output = new ctstack(expression.length());
 ctstack *stack = new ctstack(expression.length());
 bool previousIsANum = false;
 for(int i = 0; i < expression.length(); i++){
  switch (expression[i]){
   case '(':
    previousIsANum = false;
    stack->cmstackPush(expression[i]);
    break;
   case ')':
    previousIsANum = false;
    char x;
    while (x != '('){
     stack->cmstackPop(x);
     output->cmstackPush(x);
    }
    break;
   case '0':
   case '1':
   case '2':
   case '3':
   case '4':
   case '5':
   case '6':
   case '7':
   case '8':
   case '9':
    cout << "A number" << endl;
    previousIsANum = true;
    output->cmstackPush(expression[i]);
    break;
   case '+':
    previousIsANum = false;
    cout << "+" << endl;
    break;
   case '-':
    previousIsANum = false;
    cout << "-" << endl;
    break;
   case '*':
    previousIsANum = false;
    cout << "*" << endl;
    break;
   case '/':
    previousIsANum = false;
    cout << "/" << endl;
    break;
   default:
    break;
  }
 }
 char i = ' ';
 while (stack->ltopOfStack > 0){
  stack->cmstackPop(i);
  output->cmstackPush(i);
  cout << i << endl;
 }
 return 0;
}

Here is the stack code (watch out!):

#include <cstdio>
#include <assert.h>
#include <new.h>
#include <stdlib.h>
#include <iostream>

 class ctstack {
 private:
  long*  lpstack ;              // the stack itself
  long  ltrue ;            // constructor sets to 1
  long  lfalse ;            // constructor sets to 0
          // offset to top of the stack
  long  lmaxEleInStack ;         // maximum possible elements of stack

 public:
  long  ltopOfStack ;

  ctstack ( long lnbrOfEleToAllocInStack )  {     // Constructor
   lfalse = 0 ;                                             // set to zero
   ltrue  = 1 ;                                            // set to one
   assert ( lnbrOfEleToAllocInStack > 0 ) ;     // assure positive argument
   ltopOfStack     = -1 ;          // ltopOfStack is really an index
   lmaxEleInStack = lnbrOfEleToAllocInStack ;    // set lmaxEleInStack to max ele
   lpstack      = new long [ lmaxEleInStack ] ;   // allocate stack
   assert ( lpstack ) ;            // assure new succeeded
  }

  ~ctstack ( ) {              // Destructor
   delete [ ]  lpstack ;                                       // Delete the stack itself
  }

  ctstack& operator= ( const ctstack& ctoriginStack) {   // Assignment
   if ( this == &ctoriginStack )          // verify x not assigned to x
    return *this ;

   if ( this -> lmaxEleInStack <
    ctoriginStack . lmaxEleInStack ) {   // if destination stack is smaller than
    delete [ ]  this -> lpstack ;        // original stack, delete dest and alloc
    this -> lpstack =           // sufficient memory
    new long [ ctoriginStack . lmaxEleInStack ] ;
    assert ( this -> lpstack ) ;           // assure new succeeded

    // reset stack size attribute
    this -> lmaxEleInStack = ctoriginStack . lmaxEleInStack ;
   }
   // copy original to destination stack
   for ( long i = 0 ; i < ctoriginStack . lmaxEleInStack ; i ++ )
    *( this -> lpstack + i ) = *( ctoriginStack . lpstack + i ) ;

   this -> ltopOfStack = ctoriginStack . ltopOfStack ;  // reset stack position attribute

   return *this ;
  }

  long cmstackPush (char lplaceInStack ) {                // Push Method
   if ( ltopOfStack == lmaxEleInStack - 1 )          // stack is full can't add element
    return lfalse ;

   ltopOfStack ++ ;            // acquire free slot

   *(lpstack + ltopOfStack ) = lplaceInStack ;         // add element

   return ltrue ;             // any number other than zero is true
  }

  long cmstackPop (char& lretrievedStackEle ) {           // Pop Method
   if ( ltopOfStack < 0 ) {          // stack has no elements
    lretrievedStackEle = -1 ;         // dummy element
    return lfalse ;
   }

   lretrievedStackEle = *( lpstack + ltopOfStack ) ;     // stack has element  -- return it

   ltopOfStack -- ;                  // stack is pop'd

   return ltrue ;                 // any number other than zero is true
  }

  long cmstackLookAtTop (char& lretrievedStackEle ) {    // Pop Method
   if ( ltopOfStack < 0 ) {          // stack has no elements
    lretrievedStackEle = -1 ;         // dummy element
    return lfalse ;
   }

   lretrievedStackEle = *( lpstack + ltopOfStack ) ;     // stack has element  -- return it

   return ltrue ;                 // any number other than zero is true
  }

  long cmstackHasAnEle (char& lretrievedTopOfStack ) {       // Has element method
   lretrievedTopOfStack = ltopOfStack ;
   return ltopOfStack < 0 ? lfalse : ltrue ;      // 0 - false stack does not have any ele
  }                 // 1 - true stack has at least one element

  long cmstackMaxNbrOfEle (char& lretrievedMaxStackEle ) {    // Maximum element method
   lretrievedMaxStackEle = lmaxEleInStack ;      // return stack size in reference var
   return ltrue ;               // Return Maximum Size of Stack
  }

 } ;

Thanks, Anthony.