1.3 Labworks  (Page 9/11)

}

~Vector(){

if (value!=NULL)

delete value;

}

};

void main()

{

Vector v(5);

v.showdata();

Vector v2(v);

v2.showdata();

}

a. Explain why the program incurs one memory error at run-time.

b. Now add the following code segment in the Vector class definition.

Vector(const Vector&v){

dimension = v.dimension;

value=new int[dimension];

for (int i=0; i<dimension; i++)

value[i]=v.value[i];

}

Check if the program still incurs the memory error or not. Explain why.

2.3) a. Test the following program in a Visual C++ environment:

class some{ // code segment a

public:

~some() {

cout<<"some's destructor"<<endl;

}

};

void main() {

some s;

s.~some();

}

What is the output of the above program during execution? Explain the output.

b. Test the following program in Visual C++ environment:

class some{ // code segment b

int *ptr;

public:

some(){

ptr= new int;

}

~some(){

cout<<"some's destructor"<<endl;

if (ptr!=NULL){

cout<<"delete heap memory"<<endl;

delete ptr;

}

}

};

void main()

{

some s;

// s.~some();

}

What is the output of the above program during execution? Explain the output.

c. In the main() function of the program in b, if we remove the two slashes (//) before the statement s.~some(); then what the result is when the program is executed ? Explain why.

2.4) Given the class definition as follows:

class Auto {

public:

Auto(char*, double);

displayAuto(char*, double);

private:

char* szCarMake;

double dCarEngine;

};

Auto::Auto(char* szMake, double dEngine){

szCarMake = new char[25];

strcpy(szCarMake, szMake);

dCarEngineSize = dCarEngine;

}

Auto::displayAuto(){

cout<<“The car make: “<<szCarMake<<endl;

cout<<“The car engine size: “<<dCarEngine<<endl;

}

void main(){

Auto oldCar(“Chevy”, 351);

Auto newCar(oldCar);

oldCar.displayAuto();

newCar.displayAuto();

}

1. Add an appropriate copy constructor to the Auto class .
2. Add an appropriate destructor to the Auto class .

c. Run all the modifications in a C++ environment.

Lab session 10: inheritance

1. objective

The objectives of Lab session 10 are (1) to get familiar with class inheritance; (2) to learn the workings of the constructor and destructor of a derived class.

This lab session will use the inheritance hierarchies in the following figure.

2. experiment

2.1) Given the Point class defined as follows.

class Point{

private:

int color;

protected:

double x;

double y;

public:

Point(double x=0, double y=0){

this->x=x; this->y=y;

}

void move(double dx, double dy){

x=x+dx;

y=y+dy;

}

~Point(){

cout<<"Destructor Point called";

}

};

Derive from the class Point, another class named Point_Derive1 class, which is defined as follows.

class Point_Derive1:public Point{

private:

double z;

public:

Point_Derive1();

void move(double dx, double dy, double dz);

~Point_Derive1();

};

a. List out the data members and member functions of the Point_Derive1 class. And determine the access specifier of each of these members.

Derive from the class Point, another class named Point_Derive2 class, which is defined as follows.

class Point_Derive2:protected Point{

private:

double z;

public:

Point_Derive1();

void move(double dx, double dy, double dz);

~Point_Derive1();

};

b. List out the data members and member functions of the Point_Derive2 class. And determine the access specifier of each of these members.