Question

Explain each line in main (you can put it in the comments) and explain why the output looks how it looks.

#include <iostream>

using namespace std;

class A

{

public:

       A()

       {

              n=0;

       }

       A(int x)

       {

              n=x;

       }

       void f()

       {

              n++;

       }

       void g()

       {

              f();

              n=n*2;

              f();

       }

       int k()

       {

              return n;

       }

       void p()

       {

              cout<<n<<endl;

       }

private:

       int n;

};

void main()

{

       A a;

       A b(2);

       A c=b;

       A d=A(3);

       a.f();

       b.g();

       c.f();

       d.g();

       d.p();

       A e(a.k() + b.k() + c.k() + d.k());

       e.p();

}

Answer 1

Greetings!!

int main()
{
A a; //create object a with initial value 0
A b(2); //create object b with initial value 2
A c=b; //create object c with initial value 2 ie the value of b is assigned to c
A d=A(3);//create object d with initial value 3
a.f(); //call function f which increment parameter 0 to 1
b.g(); //call function g which call f() ie n=3 then n=n*2 ie n=6 then f() ie 7
c.f(); // =incremented to 3
d.g(); //f() ie n=4 then n=n*2 ie n=8 then f() ie 9
d.p(); //prints 9
A e(a.k() + b.k() + c.k() + d.k()); //sum of 1+7+3+9=20
e.p(); //prints 20
return 0;

}

Output screenshot:

Hope this helps