Class creation [Begineer in programming]

Question

It's my first code with classes. the dev c++ compiler find 4 errors so i need a help. I think there's something wrong in my concept may be This was the Header file "complex.h"

class complex{
  public:
         bool ReadComplex();
  private:
          double real;
          double imag;
  };

This is the .cpp file

#include "complex.h"
#include <iostream.h>
#include <math.h>

using namespace std;

bool complex::ReadComplex()
 { cout<<"Enter the real part";
   cin>>real;
   cout<<"Enter the imaginary part";
   cin>>imag;
   return true;
                       }

and i got 4 errors

C:/Dev-Cpp/include/c++/3.4.2/mingw32/bits/c++config.h:57: error: expected unqualified-id before "namespace"

C:/Dev-Cpp/include/c++/3.4.2/mingw32/bits/c++config.h:57: error: expected ,' or;' before "namespace"

C:/Dev-Cpp/include/c++/3.4.2/mingw32/bits/c++config.h:61: error: expected namespace-name before ';' token

C:/Dev-Cpp/include/c++/3.4.2/mingw32/bits/c++config.h:61: error: `' is not a namespace

Thanks a lot,

It makes no sense whatsoever to ask for help with errors and not even state what errors you are getting. — Jonathan Wood
– Jonathan Wood, Commented Apr 17, 2011 at 18:56
If you edit the code in the question, please state what you changed! Now the error messages is not for the code you have shown. — Bo Persson
– Bo Persson, Commented Apr 17, 2011 at 19:58

Mahesh · Accepted Answer · 2011-04-17 18:54:37Z

6

class definition should end with a ;

class complex
{
    // ....
} ;
//^ missing semi-colon

answered Apr 17, 2011 at 18:54

Mahesh

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Comments

Sarfaraz Nawaz · Accepted Answer · 2011-04-17 18:55:37Z

2

You forgot the semicolon at the end of the class definition:

class complex{

}; //<------- here put a semicolon

answered Apr 17, 2011 at 18:55

Sarfaraz Nawaz

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Comments

wilhelmtell · Accepted Answer · 2011-04-17 19:14:34Z

2

Make sure you put the class in your own named namespace, or else not say using namespace std. There's a std::complex type, and although you don't include its header, implementors are allowed to include it themselves in any of the standard headers.
End your class definition with a semicolon: class complex { /* ... */ };
Don't use <iostream.h>. Use <iostream>. Things there are in the std:: namespace, by the way.
What's <Math.h>? Is it some 3rd party library you're using that's installed outside your project tree? If it's your own code or inside your project tree then use double quotes, not angle brackets. Double quotes ask the compiler to search for the code in your tree, whereas angle brackets ask the compiler to look in system directories.
Are you sure the standard math header won't do? Take a look at the <cmath> header.

You should also

make GetReal() and GeatImag() const functions. If the Get or Set counterparts don't do anything special you should throw them away and set the member data public. This because less code is less bugs.
You should take parameters as const references whenever it makes sense. Like in complex::Add(), for example, which should be a const function too if it doesn't change the object.

edited Apr 17, 2011 at 19:14

answered Apr 17, 2011 at 19:09

wilhelmtell

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2 Comments

eslam saad Over a year ago

i tried math.h and it works in my compiler <cmath> and <iostream> give error without .h

wilhelmtell Over a year ago

@eslam everything in <iostream>, <cmath> and other standard headers is inside the std namespace. <iostream.h> is deprecated, don't use it. Similarly, you should use <cmath> and not <math.h> in C++ code. Just make sure you say std::cout and not cout. Similarly for anything else you use from these headers.

Beta · Accepted Answer · 2011-04-17 19:01:00Z

1

Your first code with classes should be:

class complex{
  };

int main()
  {
    return(0);
  }

Seriously. Get this to work, with no compiler warnings. Then add complexity a little at a time, and never add to code that doesn't work.

answered Apr 17, 2011 at 19:01

Beta

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