C++ beginner segmentation fault - c++

Question

I am reading this book called "C++ How to Program" from Deitel and I am still a beginner in this. I know Java, so I am trying to get familiar with the C++ syntax and how it works.
My code is the following:
file >> gradebook_interface.h
#include <string>
//#include <unordered_map>
using namespace std;
//specifing interface
class gradebook_interface
{
public:
//constructor
gradebook_interface(string);
void reset_Coursename();
void setCoursename(string);
string getCourseName();
void displayMessage();
void add_to_hashmap(string,int);
private:
//hashmap init
//unordered_map <string, int> course_map;
string courseName;
};
file >> gradebook_interface.cpp
#include <iostream>
//including interface "gradeinterface"
#include "gradebook_interface.h"
using namespace std;
//constructor from interface
gradebook_interface::gradebook_interface(string name)
{
setCoursename(name);
}
void gradebook_interface::setCoursename ( string name )
{
courseName = name;
}
string gradebook_interface::getCourseName()
{
return courseName;
}
void gradebook_interface::displayMessage()
{
cout << "First C++ application\n" << getCourseName() << "!" << endl;
}
//interfac's methods
void gradebook_interface::reset_Coursename()
{
courseName = "null";
cout << "The course name has been reseted! Value is: " << getCourseName() << endl;
}
void gradebook_interface::add_to_hashmap(string, int)
{
//course_map["test_course"] = 14;
//cout << "Hashmap value just entered:" << endl;
//cout << course_map["test_course"] << endl;
}
file >> gradebook_main.cpp
#include <iostream>
#include "gradebook_interface.h"
using namespace std;
int main()
{
gradebook_interface gradebook_1 ("Maths");
gradebook_interface gradebook_2 ("Greek");
cout << "gradebook 1 " << gradebook_1.getCourseName() << endl;
cout << "gradebook 2 " << gradebook_2.getCourseName() << endl;
};
The book uses Visual Studio that I can't use because I am on ubuntu.
I read somewhere that if you compile C++ code using "gcc" it invokes automatically "g++".
But I get an error, so I am forced to use g++.
My first question is, can I use gcc (any parameters needed?)?
My second question is, how does the linker works?
My third question is why do I get a segmentation fault when I try to run this ??
thanks

Answer 1

I have no problem compiling your program in this way:
g++ -O2 -g main.cpp gradebook_interface.cpp -o main
In fact I used the following Makefile
all: main
main: main.cpp gradebook_interface.cpp
g++ -O2 -g $^ -o $#
and simple issued make && ./main outputting:
gradebook 1 Maths
gradebook 2 Greek
I ran it under valgrind; so far no detected memory errors. I haven't looked at your code
Edit On the How does the linker work part:
If you rewrote that Makefile like so:
all: main
CPPFLAGS+=-O2 -g
main: main.o gradebook_interface.o
g++ $(CPPFLAGS) $^ -o $#
It would result in the following build steps:
g++ -O2 -g -c -o main.o main.cpp
g++ -O2 -g -c -o gradebook_interface.o gradebook_interface.cpp
g++ -O2 -g main.o gradebook_interface.o -o main
which shows how to do the compile steps (-c) separately from the link step. The link step could in that case be written as the explicit call to ld intead, but you'll have to specify the runtime libraries for libgcc and libstdc++ yourself