* Write a program to overload (++) operator.

#+ATTR_LATEX: :options frame=single,breaklines=true
#+begin_src cpp :tangle 19.cpp :results output :exports both :wrap src text
#include <iostream>
using namespace std;

class Foo {
  int x;

public:
  Foo(int _x) { x = _x; };
  Foo &operator++();
  int get() { return x; }
};

Foo &Foo::operator++() {
  x++;
  return *this;
}

int main() {
  Foo bar = Foo(-3);
  ++bar;
  cout << bar.get();
}
#+end_src

#+LATEX: \clearpage

* Write a program to overload + operator.

#+ATTR_LATEX: :options frame=single,breaklines=true
#+begin_src cpp :tangle 20.cpp :results output :exports both :wrap src text
#include <iostream>
using namespace std;

class Foo {
  int x;

public:
  Foo(int _x) { x = _x; };
  Foo operator+(Foo);
  int get() { return x; }
};

Foo Foo::operator+(Foo bar) {
  return Foo(x + bar.get());
}

int main() {
  Foo bar = Foo(-3);
  Foo baz = Foo(8);

  cout << (bar + baz).get();
}
#+end_src

#+LATEX: \clearpage

* Write a program to overload * operator.

#+ATTR_LATEX: :options frame=single,breaklines=true
#+begin_src cpp :tangle 21.cpp :results output :exports both :wrap src text
#include <iostream>
using namespace std;

class Foo {
  int x;

public:
  Foo(int _x) { x = _x; };
  Foo operator*(Foo);
  int get() { return x; }
};

Foo Foo::operator*(Foo bar) {
  return Foo(x * bar.get());
}

int main() {
  Foo bar = Foo(-3);
  Foo baz = Foo(8);

  cout << (bar * baz).get();
}
#+end_src