Help with Unresolved External.

[CoolDudeMan]

I'm currently working on a class "Course" and I'm getting an
unresolved external error when trying to compile.

I understand that unresolved externals are caused by declaration of
methods that are not defined, but I think I defined all my methods so
this one has got me stumped. Any help would be much appreciated.

Thank you for your time,

Kyle

course.h
--------
#ifndef COURSE_H
#define COURSE_H

#include <string>
using namespace std;

class Course
{
private:
string id;
int credithours;
string instructor;
string days;
string time;
string room;
int capacity;
string roster[50];
int size;
public:
Course();// Default Constructor
void ReadCourse(istream & fin);// Reads course information from
file.
void WriteCourse(ostream & fout);// Writes course information to
file.
void PrintData();// Prints's all data except roster to screen with
labels.
void PrintRoster(ostream & out);// Prints Roster to any output
stream.
void AddStudent(ostream & out, string newstudent);// Adds student to
roster.
};

#endif


Course.cpp
----------
#include "course.h"
#include <iostream>
using namespace std;

Course::Course()
{
id="0";
}

void Course::ReadCourse(istream & fin)// Reads course information from
file.
{
fin >> id;
fin >> credithours;
getline(fin, instructor);
fin >> days;
getline(fin, time);
getline(fin, room);
fin >> capacity;
fin >> size;
for (int i=0; i<=size; i++)
{
getline(fin, roster);
}
}

void Course::WriteCourse(ostream & fout)// Writes course information
to file.
{
fout << id << " " << credithours << "\n";
fout << instructor << "\n";
fout << days << " " << time << "\n";
fout << room << "\n";
fout << capacity << " " << size << "\n";
for (int i=0; i<=size; i++)
{
fout << roster << "\n";
}
}

void Course:rintData()// Prints's all data except roster to screen
with labels.
{
cout << "Course ID: " << id << endl;
cout << "Credits: " << credithours << endl;
cout << "Instructor: " << instructor << endl;
cout << "Days and Time: " << days << " " << time << endl;
cout << "Capacity: " << capacity << endl;
cout << "Enrolled: " << size << endl;
}

void Course:rintRoster(ostream & out)// Prints Roster to any output
stream.
{
for (int i=0; i<=size; i++)
{
out << roster << endl;
}
}

void Course::AddStudent(ostream & out, string newstudent)// Adds
student to roster.
{
size+=1;
roster[size]=newstudent;
}

ERROR:
LIBCD.lib(crt0.obj) : error LNK2019: unresolved external symbol _main
referenced in function _mainCRTStartup
Debug/Project 1.exe : fatal error LNK1120: 1 unresolved externals

 

[Karl Heinz Buchegger]

I'm currently working on a class "Course" and I'm getting an
unresolved external error when trying to compile.

It is the *linker* which emits this message, not the compiler.
The linker is trying to assemble the complete executable. And in doing
so, it noticed that:

ERROR:
LIBCD.lib(crt0.obj) : error LNK2019: unresolved external symbol _main
referenced in function _mainCRTStartup
Debug/Project 1.exe : fatal error LNK1120: 1 unresolved externals

There is no main() function in your program!

 

[CoolDudeMan]

Ah, doh.

My apologies for my vocabulary (still learning all this stuff. )
but I see the problem now. You just can't build solutions without
having a mainline function to execute it.

So, in the future, as long as it gets to the "Linking..." step w/o any
errors, than the classes and it's implementation and interface files
are okay.

Thanks for the help Karl!

-Kyle