Thread: Compilation error wrt types + constructors

Hi Everyone.
I am new to c++, and trying to complete an assignment. I have to create a class called 'Element', declare it in a header, implement it in a c++ file. When i try and compile it to object code (-c flag on g++), I get the following error:

g++ -c Element.cpp
Element.cpp:5: error: new types may not be defined in a return type
Element.cpp:5: error: return type specification for constructor invalid


here is the code for the .h:

Code:

//Element.h an item implementation to hold any queue/stack data.
#ifndef ELEMENT_H
#define ELEMENT_H

class Element{
 public:
  Element(int* newItem);
  int* getItem();
  void setNext(Element*);
  Element * getNext();

 private:
  int * item;
  Element* next;
}

#endif

and the .cpp:

/

Code:

/Element.cpp implementation to hold data element
#include <stdio.h>
#include "Element.h"

Element::Element(int * newItem){
  item = newItem;
}

int* Element::getItem(){
  return item;
}

void Element::setNext(Element* newNext){
  next = newNext;
}

Element* Element::getNext(){
  return next;
}

all the research i have done on this compilation error points to the lack of a semi-colon after a struct... so I really dont know what im looking for. Any ideas on how to fix this?

In addition, I later have to alter this class so it can store any type, not just 'int', using a template. Can anyone tell me where I can start looking to figure out how to do that?

Thanks

Common mistake, forgot the semicolon:

Code:

//Element.h an item implementation to hold any queue/stack data.
#ifndef ELEMENT_H
#define ELEMENT_H

class Element{
 public:
  Element(int* newItem);
  int* getItem();
  void setNext(Element*);
  Element * getNext();

 private:
  int * item;
  Element* next;
};  // Missing semicolon

#endif

Originally Posted by thebudbottle

Thank you, thank you very much. Do you know where I could get info on using templates to allow me to pass any data type, as opposed to just int?

Thanks again

Well, google should be able to help with sources on explaining templates. But... to start with:

Code:

template <typename T>
class Element{
 public:
  Element(T* newItem);
  T* getItem();
  void setNext(Element*);
  Element * getNext();

 private:
  T * item;
  Element* next;
};

// Put code from CPP source file into header here and delete the souce file
// Make changes to this source similar to changes made above

One thing to note, with templates, you can't really have them separately as a header file and a source file (you can but you need a special compiler [Comeau(?) I think]). All the code must be in the header file as indicated by the note above.