C++ Book Exercices

[impetus]

Hello there!.

Could not compile with error:

root@supernova-MacBookPro:/home/supernova/Desktop/Impetus/Prog/Nov# g++ GradeBook.cpp -o GradeBookcpp
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status

GradeBook.H
GradeBook.cpp


GradeBook.H

#include <string> // class GradeBook uses C++ standard string class
// GradeBook class definition
class GradeBook
{
public:
explicit GradeBook( std::string ); // constructor initialize courseName
void setCourseName( std::string ); // sets the course name
std::string getCourseName() const; // gets the course name
void displayMessage() const; // displays a welcome message
private:
std::string courseName; // course name for this GradeBook
}; // end class GradeBook 

GradeBook.cpp

#include <iostream>
#include "GradeBook.h" // include definition of class GradeBook
using namespace std;
// constructor initializes courseName with string supplied as argument
GradeBook::GradeBook( string name )
: courseName( name ) // member initializer to initialize courseName
{
// empty body
} // end GradeBook constructor
// function to set the course name
void GradeBook::setCourseName( string name )
{
courseName = name; // store the course name in the object
} // end function setCourseName
// function to get the course name
string GradeBook::getCourseName() const
{
return courseName; // return object's courseName
} // end function getCourseName
// display a welcome message to the GradeBook user
void GradeBook::displayMessage() const
{
// call getCourseName to get the courseName
cout << "Welcome to the grade book for\n" << getCourseName()
<< "!" << endl;
} // end function displayMessage 

Please Advise!

[seeplus]

You need a function called int main() defined in the program

[impetus]

// Fig. 3.12: GradeBook.cpp
// GradeBook member-function definitions. This file contains
// implementations of the member functions prototyped in GradeBook.h.
#include <iostream>
#include "GradeBook.h" // include definition of class GradeBook
using namespace std;
// constructor initializes courseName with string supplied as argument


int main ()
{

GradeBook::GradeBook( string name )
: courseName( name ) // member initializer to initialize courseName
{
// empty body
} // end GradeBook constructor
// function to set the course name
void GradeBook::setCourseName( string name )
{
courseName = name; // store the course name in the object
} // end function setCourseName
// function to get the course name
string GradeBook::getCourseName() const
{
return courseName; // return object's courseName
} // end function getCourseName
// display a welcome message to the GradeBook user
void GradeBook::displayMessage() const
{
// call getCourseName to get the courseName
cout << "Welcome to the grade book for\n" << getCourseName()
<< "!" << endl;
} // end function displayMessage

}

how can i ammend this to make it proper?
Error ouput:

// Fig. 3.12: GradeBook.cpp
// GradeBook member-function definitions. This file contains
// implementations of the member functions prototyped in GradeBook.h.
#include <iostream>
#include "GradeBook.h" // include definition of class GradeBook
using namespace std;
// constructor initializes courseName with string supplied as argument


int main ()
{

GradeBook::GradeBook( string name )
: courseName( name ) // member initializer to initialize courseName
{
// empty body
} // end GradeBook constructor
// function to set the course name
void GradeBook::setCourseName( string name )
{
courseName = name; // store the course name in the object
} // end function setCourseName
// function to get the course name
string GradeBook::getCourseName() const
{
return courseName; // return object's courseName
} // end function getCourseName
// display a welcome message to the GradeBook user
void GradeBook::displayMessage() const
{
// call getCourseName to get the courseName
cout << "Welcome to the grade book for\n" << getCourseName()
<< "!" << endl;
} // end function displayMessage

}

[seeplus]

Move L10 & 11 to before L36

[impetus]

Yes, i did so, but there is not output in this case. Added lines for some ouput. Everything's fine now! Thank u

[impetus]

Just got back to my exercises! Could you please with correct syntax with below
Now I have the compilation error:

3.12.cpp:5:1: error: no declaration matches ‘GradeBook::GradeBook(std::string, std::string)’
5 | GradeBook::GradeBook(string name, string name2)
| ^~~~~~~~~

// Fig. 3.11: GradeBook.h
// GradeBook class definition. This file presents GradeBook's public
// interface without revealing the implementations of GradeBook's member
// functions, which are defined in GradeBook.cpp.
#include <string> // class GradeBook uses C++ standard string class
// GradeBook class definition
class GradeBook
{
public:
explicit GradeBook( std::string ); // constructor initialize courseName
void setCourseName( std::string ); // sets the course name
void setInstructorName( std::string ); // sets the course name

std::string getCourseName() const; // gets the course name
void displayMessage() const; // displays a welcome message
private:
std::string courseName;
std::string instructorName; // course name for this GradeBook
}; // end class GradeBook 

#include <iostream>
#include "GradeBook.h" // include definition of class GradeBook
using namespace std;
// constructor initializes courseName with string supplied as argument
GradeBook::GradeBook(string name, string name2)
:courseName (name), instructorName(name2)
{
// empty body
} // end GradeBook constructor




// function to set the course name
void GradeBook::setCourseName( string name )
{
courseName = name; // store the course name in the object
} // end function setCourseName
// function to get the course name
string GradeBook::getCourseName() const
{
return courseName; // return object's courseName
} // end function getCourseName
// display a welcome message to the GradeBook user
void GradeBook::displayMessage() const
{
// call getCourseName to get the courseName
cout << "Welcome to the grade book for\n" << getCourseName()
<< "!" << endl;
} // end function displayMessage

void GradeBook :: setInstructorName (string name)
{
}

int main ()
{


}

//(Modifying Class GradeBook ) Modify class GradeBook (Figs. 3.11–3.12) as follows:
//a) Include a second string data member that represents the course instructor’s name.
//b) Provide a set function to change the instructor’s name and a get function to retrieve it.
//c) Modify the constructor to specify course name and instructor name parameters.
//d) Modify function displayMessage to output the welcome message and course name,
//then the string "This course is presented by: " followed by the instructor’s name. 

[salem c]

> Could not compile with error:
> root@
The first thing I would suggest you do is stop doing s/w development in your super user root account.
Bugs in your programs will be capable of doing a lot more damage.

[AbstractionAnon]

.h line 11: The declaration for your constructor accepts only a single string.

.cpp line 6: Your definition of the constructor takes two strings. As the error messages is telling you, the declarations and the definition must match.