C++ Class / Header file example

Car.cpp

#import "Car.h"

const int ACCELERATION_FACTOR = 10;
const int BRAKING_FACTOR = 30;

Car::Car() {
  speed = 0;
}

void Car::accelerate(float intensity) {
  speed = speed + ACCELERATION_FACTOR * intensity;
}

void Car::brake(float intensity) {
  speed = speed - BRAKING_FACTOR * intensity;
}

Car.h

class Car
{
public:
  Car();
  void accelerate(float intensity);
  void brake(float intensity);
private:
  int speed;
}

Race.cpp

Car *myCar = Car::Car();
myCar->accelerate(1.0);
myCar->brake(0.5);

Can you re-post with cleaner look ? Difficult to understand the issue from this copy/paste.

Try

#include"panel.h"
panel::panel()
{
    this->x = 0;
}/** end construction */

void panel::set_x( int x )
{
    this->x = x;
}/** end method */

and build with g++ -o main.x main.cpp panel.cpp