[RESOLVED] error LNK2019: unresolved external symbol???

I don't know why I'm getting this error, this is a post fix calculator for array use review, I'll include only the push functions to save post space. If i comment out the push/pops, the errors does not occur.

The fatal errors:

Code:

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error LNK2019: unresolved external symbol "public: void __thiscall stack::pop(int &)" (?pop@stack@@QAEXAAH@Z) referenced in function _main
1>client.obj : error LNK2019: unresolved external symbol "public: void __thiscall stack::push(int)" (?push@stack@@QAEXH@Z) referenced in function _main

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The client program (part of)

Code:

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stack myStack;
int arg1;  // this will hold the left operand.
int arg2; //this will hold the right operand.
int result; // result of every calculation, to be pushed onto stack.
int m;

int main()
{
        string s1;
        cout << "Input the numbers followed by operator(s): " << endl;
        cin >> s1;
       
        for (int i=0;s1[i]!='\0';i++)
        {
                if (isdigit(s1[i])){  //used isdigit to check if number, if true; push.
                        m = (int)s1[i];
                        cout << m << endl;
                myStack.push(m);
                }else if(s1[i]=='+'){
                        myStack.pop(arg1); //pops operand off top of stack and into arg1 which is a int data
...........................................

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The stack.h and stack.cpp PUSH code:

Code:

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typedef int el_t;    // the el_t type is int for now
                    // el_t is unknown to the client


class stack
  {

  private: // to be hidden from the client

        el_t    el[MAX];      // el is  an array of el_t's --int's

.........................

                void push(el_t);

......................cpp below

void stack::push(el_t n) 
{
  if (isFull())
          throw Overflow();
  else{
          top++;
          el[top] = n;
  }
}

---

Looks like you forgot to add the implementation file for stack to your project.
Kurt

Quote:

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Originally Posted by ZuK

Looks like you forgot to add the implementation file for stack to your project.
Kurt

---

Implementation file is the stack.cpp file mentioned above with the code:

Code:

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void stack::push(el_t n) 
{
  if (isFull())
          throw Overflow();
  else{
          top++;
          el[top] = n;
  }
}

---

(and more but only included what I thought would be relevant.

That is, if I understand what an 'implementation file' is...

Yes. stack.cpp is the implementation file for the stack class.
As long as you're not posting compilable code, all I can do is guessing.
Kurt

Compilable code:

Stack.h

Code:

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int const MAX = 10;  // The MAX number of elements for the stack
                    // MAX is unknown to the client
                                // MAX is to prevent double digit numbers.

typedef int el_t;    // the el_t type is int for now
                    // el_t is unknown to the client


class stack
  {

  private: // to be hidden from the client

        el_t    el[MAX];      // el is  an array of el_t's --int's
        int      top;          // top is index to the top of stack
        void stackError(char*); // utility function for error handling

  public: // prototypes to be used by the client

              stack();  // constructor
              ~stack();  // destructor to get rid of object

                class Overflow{};  //exception to be thrown  //"withing stack class"???
                class Underflow{};  //exception to be thrown

        // How to call: format stackname.push(argument)
        // PURPOSE: if not full, enters an element at the top
                void push(el_t);

        // How to call: format stackname.push(pass by reference argument)
        // PURPOSE: if not empty, removes and gives back the top element
        void pop(el_t&);  //Pass by reference, get element back as arg

        // HOW TO CALL: stackname.push(pass by reference argument)
        // PURPOSE: if not empty, gives the top element without removing it
        void topElem(el_t&); //Pass by reference, get element back as arg

                // How to call:  stackname.isEmpty();
                // PURPPOSE: returns true is stack is empty, else false 
              bool isEmpty(); 

                // How to call:  stackname.isFull();
                // PURPPOSE: returns true if stack is full, else false
              bool isFull();         

                // How to call:  stackname.displayAll();
                // PURPPOSE: display all elements in el_t, vertically.  Non distructive.
        void displayAll();
                // How to call:  stackname.clearIt();
                // PURPPOSE: Clear the entire stack.
        void clearIt();
       
  }; 

// Note: semicolon is needed at the end of the header file

---

stack.cpp:

Code:

---

#include <iostream>
using namespace std;

#include "stack.h"


// PURPOSE: constructor which initializes top
stack::stack()
{
  top = -1;
}


// PURPOSE: destructor which does nothing for the static array
stack::~stack() {
  /* nothing to do since this is a static array */
}


// PURPOSE: (private) to handle unexpected errors encountered by other methods
// PARAMS:  a string message to be displayed
// ALGORITHM: simply cout the message and exit from the program
void stack::stackError(char* msg)
{ cout << msg << endl; exit(1); }



// PURPOSE: (public) to push element onto top of el[] stack if not full.
// PARAMS:  A number to be checked then pushed
// ALGORITHM: use isFull to if stack is full,
        //if not increase top by 1 and copy n to that new spot.
void stack::push(el_t n) 
{
  if (isFull())
          throw Overflow();
  else{
          top++;
          el[top] = n;
  }
}

// PURPOSE: (public) to pop element off of top of el[] stack if not empty.
// PARAMS:  A number to be checked then pushed
// ALGORITHM: use isEmpty to if stack is empty,
        //if not; copy top spot to n and decrease top by 1.
void stack::pop(el_t& n)
{
  if (isEmpty())
          throw Underflow();
  else {
          n = el[top];
          top--;
  }
}


// PURPOSE: (public) to give top element of stack if not empty
// PARAMS:  argument to be checked
// ALGORITHM: calls isEmpty and if true, throws underflow exception
        //else, gives back top element of el.
void stack::topElem(el_t& n)
{
        if(isEmpty())
                throw Underflow();
        else
                n = el[top];
}


// PURPOSE: (public) checks stack to see if elements do not exist exist (empty)
// PARAMS:  returns bool.
// ALGORITHM: checks top, if top <0, stack is empty, return true.  Else false.
bool stack::isEmpty() {
  if (top==-1)
          return true;
  else
          return false;
}


// PURPOSE: (public) checks stack to see if 10 single digit elements exist (full)
// PARAMS:  returns bool.
// ALGORITHM: checks top, if top >9, stack is full, return true.  Else false.
bool stack::isFull() {
  if (top==MAX-1)
          return true;
  else
        return false;
}


// PURPOSE: (public) displays all existing elements of stack.
// PARAMS:  None.
// ALGORITHM: calls isEmpty.  If false displays elements vertically. If true displays '[empty]
void stack::displayAll()
{
  if (isEmpty()) cout << "[ empty ]" <<endl;
  else
    for (int i = top; i >= 0; i--)
      {  cout << el[i] << "\n" << endl; }
}

// PURPOSE: (public) Clears the stack of elements if not already empty.
// PARAMS:  None. Void.
// ALGORITHM: while not isEmpty, keep popping the stack
void stack::clearIt()
{
  while(!isEmpty())
          pop(el[top]);
}// the end

---

client.cpp

Code:

---

#include <stdlib.h>
#include <iostream>
#include <string>
#include <sstream>
#include "stack.h"

using namespace std;

stack myStack;
int arg1;  // this will hold the left operand.
int arg2; //this will hold the right operand.
int result; // result of every calculation, to be pushed onto stack.
int m;

int main()
{
        string s1;
        cout << "Input the numbers followed by operator(s): " << endl;
        cin >> s1;
       
        for (int i=0;s1[i]!='\0';i++)
        {
                if (isdigit(s1[i])){  //used isdigit to check if number, if true; push.
                        m = (int)s1[i];
                        cout << m << endl;
                myStack.push(m);
                }else if(s1[i]=='+'){
                        myStack.pop(arg1); //pops operand off top of stack and into arg1 which is a int data
                        myStack.pop(arg2); //pops operand off top of stack and into arg2 which is a int data
                        result = arg1 + arg2;
                        cout << "arg1 and arg2 and result: " << arg2 << " " << arg1 << " " << (int)result-48 << endl;
                        myStack.push((int)result-48); //HOW TO INPUT RESULT?????
                } else
                        cout << "else called from client" << endl;
                       
        }

        myStack.displayAll();


/*  WORKING BELOW
if(!myStack.isFull())
        myStack.push('A');
//else
//throw OverFlow();
myStack.displayAll();
char C;
if (!myStack.isEmpty())
        myStack.pop(C);  //pop INTO C
//else
//throw UnderFlow();
myStack.displayAll();

cout << C << endl;
*/
       
system("PAUSE");

}

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Compiles fine for me.
So my first statement holds. Did you add stack.cpp to the project ?
Kurt

Quote:

---

Originally Posted by ZuK

Compiles fine for me.
So my first statement holds. Did you add stack.cpp to the project ?
Kurt

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resolved. Good call, ZuK, for turning my attention to Visual Studio.

I copied all the source files to the local folder after working on the project from a different location, on a thumb drive. I also changed the stack.cpp file name. Resolved by compiling stack.cpp before compiling client.