expected `)' before str... help!

[dingobiatch]

Almost got everything debugged in my code, but I'm having this error:
integer.h:9: error: expected `)' before ‘astr’

Header:

#ifndef INTEGER_H
#define INTEGER_H

class Integer{
 private:
  int _int;
 public:
  Integer(int i);
  Integer(std::string astr);

  int getValue();
  void setValue(int i);
  void add(Integer& i);
  void subtract(Integer& i);
  void multiply(Integer& i);
  void divide(Integer& i);
};
#endif

Cpp:

#include <iostream>
#include <string>
#include "integer.h"

Integer::Integer(int i){
  _int = i;
}

Integer::Integer(std::string astr){
  _int = atoi(astr.c_str());
}

int Integer::getValue(){
  return _int;
}

void Integer::setValue(int i){
  _int = i;
}

void Integer::add(Integer& i){
  _int += i.getValue();
}

void Integer::subtract(Integer& i){
  _int -= i.getValue();
}

void Integer::multiply(Integer& i){
  _int *= i.getValue();
}

void Integer::divide(Integer& i){
  if(i.getValue() !=0 ) _int /= i.getValue();
  else {
    std::cout << "Cannot divide by zero!\n";
    exit(-1);
  }
}

What is causing this issue??

[cyberfish]

works fine here (gcc 4.2.3, 64-bit Linux).

By the way, identifiers starting with an underscore are by convention reserved for implementation's internal use (compilers and standard libraries).

[dingobiatch]

Killed the underscore, change it to myInt. Still doesn't work.
This is amazing. Why won't this work on my system???

[cyberfish]

what compiler?

Also, post the whole compiler output.

[dingobiatch]

I'm using g++ (GCC) 4.1.2 20070626.

New to c++ and g++, what would the whole compiler output include? that is the only error i have.

[cyberfish]

hmm that is strange

what command did you use to compile?
I used

g++ -c integer.cpp

since integer.cpp doesn't have a main().

[brewbuck]

Maybe your string header file is messed up.

[MarkZWEERS]

You probably miss the header file 'string'.
Just put the line

#include <string>

after the "#define INTEGER_H"

Ah, I see you've only included it in the .cpp file. This means you cannot use types from this header in your .h file. Include it in the .h file instead and it will work.

Your functions 'add', 'subtract', 'multiply', 'divide' are in fact operators '@=' instead of functions. Consider the following:

#ifndef INTEGER_H
#define INTEGER_H

#include <string>

class Integer{
 private:
  int _int;
 public:
  Integer(int i);
  Integer(std::string astr);

  int getValue() const;           // const declaration
  void setValue(int const& i); // const declaration of argument 

  Integer& operator +=(Integer const& i);
};
#endif

inline
int Integer::getValue() const
{
  return _int;
}

Integer& Integer::operator+=( Integer const& p_int)
{
  this->_int += p_int.getValue();
  return *this;
}

#endif

Now you can implement an operator+ accordingly:

Integer operator+( Integer const& p_arg1, Integer const& p_arg2)
{
  Integer result( p_arg1);
  return ( result += p_arg2);
}

[brewbuck]

Ah, I see you've only included it in the .cpp file. This means you cannot use types from this header in your .h file. Include it in the .h file instead and it will work.

In this case <string> was included first, so its definitions are available to the other header. Not the best practice, but also not the cause of the problem.

[Daved]

I think it probably is the cause of the problem.

If there is another source file that uses the Integer class but doesn't #include <string> then you will get that exact error when you compile the file.

[brewbuck]

I think it probably is the cause of the problem.

If there is another source file that uses the Integer class but doesn't #include <string> then you will get that exact error when you compile the file.

So the problem report was incomplete. Wouldn't be the first time!