Doing a quiz..what is wrong?

[Sesshzakuto]

OK so I noticed a few things that are very confusing.. maybe someone can explain to me what is going on and why? Here are my files..


// quiz1.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>
#include "io.cpp"
using namespace std;

int readnumber();
int writenumber();

int main()
{
readnumber1();
readnumber2();
writenumber();
return 0;
}

------------------------------------

and the attached file..

------------------------------------

#include "stdafx.h"
#include <iostream>
using namespace std;
int x;
int y;
int readnumber1()
{
cout << "Enter a number to add. " << endl;

cin >> x;

return x;
}

int readnumber2()
{
cout << "Now enter another number to add. " << endl;
cin >> y;
return y;
}



void writenumber()
{
cout << "The answer is " << x+y << endl;
}

############################################################
############################################################

It is giving me this error..

1>learncppquiz.obj : error LNK2005: "int __cdecl readnumber1(void)" (?readnumber1@@YAHXZ) already defined in io.obj
1>learncppquiz.obj : error LNK2005: "int __cdecl readnumber2(void)" (?readnumber2@@YAHXZ) already defined in io.obj
1>learncppquiz.obj : error LNK2005: "void __cdecl writenumber(void)" (?writenumber@@YAXXZ) already defined in io.obj
1>learncppquiz.obj : error LNK2005: "int x" (?x@@3HA) already defined in io.obj
1>learncppquiz.obj : error LNK2005: "int y" (?y@@3HA) already defined in io.obj
1>c:\users\gern\documents\visual studio 2010\Projects\learncppquiz\Debug\learncppquiz.exe : fatal error LNK1169: one or more multiply defined symbols found
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========



################################################################################################################################################################

Here's the thing though as I play with it and I change where I plug x and y in on the code it tells me that they are *undeclared

[Jacobhaha]

As far as i can see there are no prototype declarations on:

readnumber1(); readnumber2();

I haven't worked with attached files before so i might be wrong.

[Sesshzakuto]

If I am understanding it right (which I must not be lol) but the attached file is supposed to take care of that because they are declared there and then called in main?

[Peter87]

Normally .cpp files should not be included. Instead create a header file containing the declarations of the functions and include that instead. You should not have to make any changes to the .cpp file.

[Jacobhaha]

As i said i haven't worked with attached files at all so i don't know when they are executed, but as i can see you have functions in there, so unless it is executing before main() in your program, i'm guessing there needs to be prototype declarations.