Requesting a function from another file in a class not working - c++

Question

I have 2 .cpp files called "FactoringProgram.cpp" and "FactoringProgram2nd.cpp", also 1 header file called "FactoringProgram.h". I've already tried searching for this problem on StackOverflow and a couple other sites and haven't found a solution that worked for me. When I try to run this command: "g++ FactoringProgram.cpp FactoringProgram2nd.cpp" I get this error:
FactoringProgram.cpp: In function ‘int main()’: FactoringProgram.cpp:8:11: error: request for member ‘InitialMessage’
in ‘Problem1’, which is of non-class type ‘Factoring()’
Problem1.InitialMessage();
The code for "FactoringProgram.h" is:
#ifndef FactoringProgram_h
#define FactoringProgram_h
#include <stdio.h>
#include <iostream>
class Factoring
{
private:
int m_FirstCoefficent;
char m_FirstOperator;
int m_SecondCoefficent;
char m_SecondOperator;
int m_3rdExpression;
public:
Factoring();
int InitialMessage();
};
#endif
FactoringProgram.cpp code:
#include <stdio.h>
#include <iostream>
#include "FactoringProgramH.h"
int main()
{
Factoring Problem1();
Problem1.InitialMessage();
return 0;
}
FactoringProgram2nd.cpp code:
#include "FactoringProgramH.h"
#include <stdio.h>
#include <iostream>
Factoring::Factoring(int FirstCoefficent=0, char FirstOperator='+',
int SecondCoefficent=1, char SecondOperator='+', int 3rdExpression=1)
: m_FirstCoefficent(FirstCoefficen), m_FirstOperator(FirstOperator),
m_SecondCoefficent(SecondCoefficent), m_SecondOperator(SecondOperator),
m_3rdExpression(3rdExpression);
{
}
int Factoring::InitialMessage()
{
std::cout << "Ok right now your expression is looking like: "
<< FirstCoefficent << "x^2 " << FirstOperator << " " << SecondCoefficent
<< " x" << SecondOperator << " " << 3rdExpression;
}

Answer 1

Your code has several small errors. Here is a version that works (you can compare and see what I had to change). A summary of the changes are:
default parameter values should be in the header file (*.h);
you cannot start variable/argument names with numbers;
int InitialMessage() doesn't return anything, so I changed it to void InitialMessage();
when you initialize fields in a constructor, the last field cannot end with a semi-colon;
fixed the most vexing parsing (per #RSahu comment) in main.cpp.
FactoringProgram.h
#ifndef FactoringProgram_h
#define FactoringProgram_h
#include <stdio.h>
#include <iostream>
class Factoring
{
private:
int m_FirstCoefficent;
char m_FirstOperator;
int m_SecondCoefficent;
char m_SecondOperator;
int m_3rdExpression;
public:
Factoring(int FirstCoefficent = 0, char FirstOperator = '+',
int SecondCoefficent = 1, char SecondOperator = '+', int thirdExpression = 1);
void InitialMessage();
};
#endif
FactoringProgram.cpp
#include "FactoringProgram.h"
Factoring::Factoring(int firstCoefficent, char firstOperator, int SecondCoefficent, char SecondOperator, int thirdExpression) :
m_FirstCoefficent(firstCoefficent),
m_FirstOperator(firstOperator),
m_SecondCoefficent(SecondCoefficent),
m_SecondOperator(SecondOperator),
m_3rdExpression(thirdExpression)
{}
void Factoring::InitialMessage()
{
std::cout << "Ok right now your expression is looking like: "
<< m_FirstCoefficent << "x^2 " << m_FirstOperator << " " << m_SecondCoefficent
<< " x" << m_SecondOperator << " " << m_3rdExpression;
}
main.cpp
#include <stdio.h>
#include <iostream>
#include "FactoringProgram.h"
int main()
{
Factoring Problem1;
Problem1.InitialMessage();
return 0;
}

Answer 2

To this error substitute:
Factoring Problem1();
by:
Factoring Problem1 = Factoring();
The problem is that the compiler is interpreting this line as a function declaration rather than a variable declaration. AS mentioned in the comments, this is known as the most vexing parser problem.
Obs: The code you posted contain many more minor errors.

Answer 3

You should define Factoring() without params and I used headers in FactoringProgram.h
FactoringProgram.h
#include <stdio.h>
#include <iostream>
class Factoring
{
private:
int m_FirstCoefficent;
char m_FirstOperator;
int m_SecondCoefficent;
char m_SecondOperator;
int m_3rdExpression;
public:
Factoring();
Factoring(int,char,int,char,int);
int InitialMessage();
};
#endif
FactoringProgram.cpp
#include "FactoringProgram.h"
int main()
{
Factoring Problem1 = Factoring();
Problem1.InitialMessage();
system("pause");
return 0;
}
FactoringProgram2nd.cpp
#include "FactoringProgram.h"
Factoring::Factoring()
{
*this = Factoring(0, '+', 1, '+', 1);
}
Factoring::Factoring(int FirstCoefficent = 0, char FirstOperator = '+',int SecondCoefficent = 1, char SecondOperator = '+', int _3rdExpression = 1) : m_FirstCoefficent(FirstCoefficent), m_FirstOperator(FirstOperator),m_SecondCoefficent(SecondCoefficent), m_SecondOperator(SecondOperator),m_3rdExpression(_3rdExpression)
{
}
int Factoring::InitialMessage()
{
std::cout << "Ok right now your expression is looking like: "
<< m_FirstCoefficent << "x^2 " << m_FirstOperator << " " << m_SecondCoefficent
<< " x" << m_SecondOperator << " " << m_3rdExpression;
return 0;
}