Every time I write a code using Visual Studio for my C++ class, I keep getting reference linking errors and I dont know how to fix it. I have attached the code and the error that I keep getting.

// Fig. 3.7: fig03_07.cpp 47
 // Instantiating multiple objects of the GradeBook class and using
 // the GradeBook constructor to specify the course name
 // when each GradeBook object is created.
 #include <iostream>
 using std::cout;
 using std::endl;

 #include <string> // program uses C++ standard string class
 using std::string;

// GradeBook class definition
 class GradeBook
 // constructor initializes courseName with string supplied as argument
 GradeBook( string name )
 setCourseName( name ); // call set function to initialize courseName
 } // end GradeBook constructor

 // function to set the course name
 void setCourseName( string name )
 courseName = name; // store the course name in the object
 } // end function setCourseName
// function to get the course name 48
 string getCourseName()
 return courseName; // return object's courseName
 } // end function getCourseName

 // display a welcome message to the GradeBook user
 void displayMessage()
 // call getCourseName to get the courseName
 cout << "Welcome to the grade book for\n" << getCourseName()
 << "!" << endl;
 } // end function displayMessage
 string courseName; // course name for this GradeBook
 }; // end class GradeBook

Errors I keep getting:
1>------ Build started: Project: class example2, Configuration: Debug Win32 ------
1>MSVCRTD.lib(crtexe.obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup
1>C:\Documents and Settings\dj000034880\Desktop\Computer Science 2\class example2\Debug\class example2.exe : fatal error LNK1120: 1 unresolved externals
1>Build log was saved at "file://c:\Documents and Settings\dj000034880\Desktop\Computer Science 2\class example2\class example2\Debug\BuildLog.htm"
1>class example2 - 2 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

commented: Excellent post - used code tags and posted error messages :) +24

Every program must have one main() function. The code you posted does not have that.

Every program must have one main() function. The code you posted does not have that.

Thank you, I didnt realize I forgot the main function. Once I added the main function it work.

Thank you again for your help.