a.cpp

#include<iostream>

using namespace std;

class MyClass{
private:

int x;

public:

MyClass()

{

x=0;

}

MyClass(int x)

{

this->x = x; /*used to retrieve the objects x

hidden by the local variable 'x'*/

}

void setX(int x)

{

this->x = x;

}

int getX()

{

return x;

}

void printX()

{

cout << "x=" << x << endl;

}

};



// Pass by value

void fun1(MyClass a)

{

a.setX(1);

}



// Pass by reference

void fun2(MyClass& a)//store the address of a into MyClass

{

a.setX(2);

}




// Pass by pointer

void fun3(MyClass* a)

{

a->setX(3);

}



// Using double pointers! Coz why stop at single pointers? :)

void fun4(MyClass** a)

{

(*a)->setX(4);

}




int main()

{

MyClass a;

MyClass* b;

MyClass** c;

cout << endl << "----Calling fun1----" << endl;

fun1(a);

a.printX(); //print 1




cout << endl << "----Calling fun2----" << endl;

fun2(a);

a.printX(); // Explaining output (1 point)



cout << endl << "----Calling fun3----" << endl;

b = &a; // Fixing compile error (1 point)

fun3(b);

a.printX(); // Explaining output (1 point)




cout << endl << "----Calling fun4----" << endl;

c = &b; // Fixing compile error (1 point)

fun4(c);

a.printX(); // Explaining output (1 point)

//Dereferencing using single pointer

cout << "\n\nTwo ways of dereferencing, \n1. Using '.' operator\n2. Using '->' operator\n\n";

b->printX(); // Fixing compile error (1 point)

b->printX(); // Fixing compile error (1 point)

// add a statement here!


cout << "\n\n----Understanding arrays as pointers----" << endl;

MyClass arr[5];

arr[0].setX(10);

arr[1].setX(20);

arr[2].setX(30);

arr[3].setX(40);

arr[4].setX(50);

cout << "----Running for loop for array variable 'arr' with 5 slots----" << endl << endl;

//Explaining for loop (2 points)

for (unsigned int i=0; i<5; i++)

{

cout << "i = " << i << endl;

cout << "memory location (arr + i) = " << arr+i << endl;

cout << " (*(arr + i)).printX() prints ";

(*(arr+i)).printX();

cout << " arr[i].printX() prints ";

arr[i].printX();

cout << endl;

}

return 0;



}