C++ Implementing a copy constructor - c++

Question

I am writing some code to implement a deep copy of an object.
Here is my code:
//---------------------------------------------------------------------------
#pragma hdrstop
#include <tchar.h>
#include <string>
#include <iostream>
#include <sstream>
#include <conio.h>
using namespace std;
//---------------------------------------------------------------------------
class Wheel
{
public:
Wheel() : pressure(32)
{
ptrSize = new int(30);
}
Wheel(int s, int p) : pressure(p)
{
ptrSize = new int(s);
}
~Wheel()
{
delete ptrSize;
}
void pump(int amount)
{
pressure += amount;
}
int getSize()
{
return *ptrSize;
}
int getPressure()
{
return pressure;
}
private:
int *ptrSize;
int pressure;
};
class RacingCar
{
public:
RacingCar()
{
speed = 0;
*carWheels = new Wheel[4];
}
RacingCar(int s)
{
speed = s;
}
RacingCar(RacingCar &oldObject)
{
for ( int i = 0; i < sizeof(carWheels)/sizeof(carWheels[0]); ++i)
{
Wheel oldObjectWheel = oldObject.getWheel(i);
carWheels[i]=new Wheel(oldObjectWheel.getSize(),oldObjectWheel.getPressure());
}
}
void Accelerate()
{
speed = speed + 10;
}
Wheel getWheel(int id)
{
return *carWheels[id];
}
void printDetails()
{
cout << carWheels[0];
cout << carWheels[1];
cout << carWheels[2];
cout << carWheels[3];
}
private:
int speed;
Wheel *carWheels[4];
};
#pragma argsused
int _tmain(int argc, _TCHAR* argv[])
{
RacingCar testCar;
testCar.printDetails();
RacingCar newCar = testCar;
newCar.printDetails();
getch();
return 0;
}
//---------------------------------------------------------------------------
For some reason, my C++ builder crashes after compiling this code. Is there anything above that is not correct that would cause this to crash. There is no compile error, the program just crashes.

Answer 1

The problem is:
Wheel *carWheels[4];
and
*carWheels = new Wheel[4];
this only allocates 4 Wheels for carWheels[0]. Along with
return *carWheels[id];
If id is not 0, this will lead to undefined behavior because, as previously stated, only the first element is a valid pointer.
Besides this, the code is horrible. Avoid raw pointers. There are much better alternatives in C++. Use std::vector or std::array where you'd use a C-array, and smart pointers where you'd use raw ones.

Answer 2

Generally in my experience, if my compiler/tool crashes, I'm probably doing something so wrong that it never even occurred to the compiler writers to check for it.
The best way to track down such things is to comment out code until it works again, then slowly bring stuff back in until you find the offending part.
As a design note, I'd say that if it were me, I'd implement a copy constructor for Wheel as well, rather than having to write a complex deep copy constructor for classes like RacingCar that use it.