Inheritance with segmentation fault - c++

Question

I'm working on inheritance right now. I have a base class called Shape, and few others as sub class. There is no compilation error. But after when i enter all the coordinates, segmentation error pops out. Inside the driver class, option when when i tried using this d[count].toString();
Shape.h
class Shape
{
protected:
string name;
bool containsWarpSpace;
public:
Shape();
Shape(string, bool);
string toString();
virtual double computeArea();
void setName (string);
// some other codes here
};
Square.h
class Square : public Shape
{
protected:
int *x;
int *y;
int area;
int vertices;
public:
double computeArea();
void setSquare(string, string, int*, int*);
string toString();
};
Square.cpp
void Square::setSquare(string name, string type, int* a, int* b)
{
setName(name);
setContainsWarpSpace (type);
vertices = 4;
x = new int[vertices];
y = new int[vertices];
for (int i = 0; i < vertices; i++)
{
x[i] = a[i];
y[i] = b[i];
}
}
string Square::toString()
{
ostringstream convert;
string s;
string type;
for (int i = 0; i < vertices; i++)
{
convert << "point " << i + 1
<< " ( "
<< x[i] << " , " << y[i]
<< " ) "<< endl;
}
s = convert.str();
return s;
}
Driver class with int main()
class Driver
{
public:
Driver();
Shape *d[];
Square *s;
int count;
int noSquare;
int noRectangle;
int noCross;
void printDetails();
void printPlan();
void option1();
void option2();
void option3();
void option4();
string convertString(string);
};
Driver.cpp. This is the default constructor,
Driver :: Driver()
{
Shape d [MAX];
s = new Square [MAX];
count = 0;
int noSquare = 0;
int noRectangle = 0;
int noCross = 0;
}
Driver::option1()
{
if (shape.compare("square") == 0)
{
tempx = new int[4];
tempy = new int[4];
for (int i = 0; i < 4; i++)
{
int j = i + 1;
cout << "Please enter x-ordinate of pt " << j << ": ";
cin >>tempx[i];
cout << "Please enter y-ordinate of pt " << j << ": ";
cin >>tempy[i];
}
s[noSquare].setSquare(shape,type, tempx,tempy);
d[count] = &s[noSquare];
d[count].toString();
}
}
int main ()
{
option1();
}

Answer 1

Change the way you declared your shape in Driver class. In the header, declare it as :
Shape* d;
and in your CPP initialize it:
d = new Shape[MAX];
Also, since you are doing inheritance and arrays and pointers, you should manage your own destructors. Because if the chil object gets destroyed, it will take parent destructor. Therefore, your destructors should be:
virtual ~Shape();
And square:
virtual ~Square();
In them, delete the pointers:
delete x; // in case of square
delete y;
And when you have arrays:
delete [] d; // in case of driver class
Otherwise it will not free memory properly. That would probably fix your problems.