#include <iostream>

using namespace std;

bool is_2 (int);
bool is_even (int);

//*******************************************************

// some boolean functions, the conditional operator, and boolalpha

int main()

{

int x, y, z;

x = 2;
y = 4;
z = 5;

if (is_even (z))
  cout << z << " is even" << endl;
else
  cout << z << " is odd" << endl;

cout << endl;

cout << x << " is 2: " << is_2(x) << endl;
cout << y << " is 2: " << is_2(y) << endl;

cout << endl;

cout << x << " is 2: " << (is_2(x) ? "true" : "false") << endl;
cout << y << " is 2: " << (is_2(y) ? "yes" : "no")    << endl;

cout << endl;

cout << x << " is 2: " << boolalpha << is_2(x) << endl;

return 0;

}

//*******************************************************

bool is_2 (int i)
  {
  bool result;
  result = (i == 2);
  return result;
  }

bool is_even (int i)
  {
  bool result;
  result = (i%2 == 0);
  return result;
  }

/* alternate code:
  if (i%2 == 0) 
    return true;
  else
    return false;
*/
  
/*******************************************************

5 is odd

2 is 2: 1
4 is 2: 0

2 is 2: true
4 is 2: no

2 is 2: true
  
*/