Error compiling c++ tutorial (programmingHelp.org) - c++

Question

I am following tutorials from youtube. It seems I have encountered an error I can't resolve by myself. The goal is to create a class called BMI, which takes users weight name and height and prints them out..
I'm trying to compile it using g++, and I suspect I'm not doing it right. Usually I just do g++ filename.cpp, as I should in this case?
The tutorial is originally in that Microsoft ....thing, I don't know it's name. Sorry
Thank you, the code is attached below.
The error
/tmp/ccRcewk3.o: In function `main':
Main.cpp:(.text+0x7d): undefined reference to `BMI::BMI()'
Main.cpp:(.text+0x89): undefined reference to `BMI::getWeight() const'
Main.cpp:(.text+0x9a): undefined reference to `BMI::getHeight() const'
Main.cpp:(.text+0xaf): undefined reference to `BMI::getName() const'
Main.cpp:(.text+0x14f): undefined reference to `BMI::~BMI()'
Main.cpp:(.text+0x184): undefined reference to `BMI::~BMI()'
collect2: ld returned 1 exit status
Main.cpp
#include <iostream>
#include <string>
#include "BMI.h"
using namespace std;
/**************************************************/
int main()
{
string name;
int height;
double weight;
cout << "Enter your name: ";
cin >> name;
cout << "Enter your height (cm): ";
cin >> height;
cout << "Enter your weight (kg): ";
cin >> weight;
BMI Student_1;
cout << endl << "Patient name: " << Student_1.getName() << endl <<
"Height: " << Student_1.getHeight() << endl <<
"Weight: " << Student_1.getWeight() << endl;
return 0;
}
/**************************************************/
BMI.h
// Header ==> Function Declarations
#include <iostream>
#include <string>
using namespace std;
// tu ide klasa
#ifndef BMI_H
#define BMI_H
class BMI
{
public:
//Default Constructor
BMI();
//Overload Constructor
BMI(string, int, double);
//Destructor
~BMI();
// Accessor functions
string getName() const;
// // // returns name of patient
int getHeight() const;
// // // returns height of patient
double getWeight() const;
// // // returns weight of patient
private:
// member variables
string newName;
int newHeight;
double newWeight;
};
#endif
BMI.cpp:
//Function definitions
#include "BMI.h"
// to access function inside a class
BMI::BMI()
{
newHeight = 0;
newWeight = 0.0;
}
BMI::BMI(string name, int height, double weight)
{
newName = name;
newHeight = height;
newWeight = weight;
}
BMI::~BMI()
{
}
string BMI::getName() const
{
return newName;
}
int BMI::getHeight() const
{
return newHeight;
}
int BMI::getWeight() const
{
return newWeight;
}
edit:
OK, thanks everyone, I got part of the problem solved. However, you got me a little confused with editing, so I will do over.
It seems that the original code is not working, and I feel it should. Anyway, the edited code from the question doesn't work either.
So, I will try to do it again. But thank you, now I know how to compile. :)
edit2:
Everything is working now, thank you very much.

Answer 1

You need to compile the main.cpp into Main.o and BMI.cpp into BMI.o.
g++ -c Main.cpp
g++ -c BMI.cpp
Then you need to link both object files into one executable (and link to the Standard C++ lib)
g++ -o myprog Main.o BMI.o -lstdc++
Run the example with
./myprog
There seem to be more bugs, I have no time to fix, please continue yourself. :-)
[marc#quadfork ~/test]$./myprog
Enter your name: foo
Enter your height (cm): 23
Enter your weight (kg): 2
Patient name:
Height: 0
Weight: 0

Answer 2

your function return noting in your BMI.cpp
try with this.
string BMI::getName() const
{
return newName;
}
int BMI::getHeight() const
{
return newHeight;
}
double BMI::getWeight() const
{
return newWeight;
}