var square = function(x) { // assign a function to a variable square that has one parameter, x.
  return x * x;
};
console.log(square(12)); // invoke square function, with 12 as the argument.
// 144

var shape = "square";
var MyFavoriteShape = function() { // this function is not using any parameter
  return shape;
}
console.log(MyFavoriteShape());
// square

var multiplyThreeNumbers = function (x,y,z) { // a function with three parameters
  return x * y * z;
}
console.log(multiplyThreeNumbers(2,3,4));
// 24

var Me = {
  name: "Glendon Philipp Baculio",
  age: 22,
};
var UseAnObjectParameter = function(xyz) { // assign an object parameter
  return "name: "+ xyz.name + " age: "+xyz.age;
}
console.log(UseAnObjectParameter(Me));

var addTwo = function(x) {
 if(isNaN(x)) {
   return;
 }
  return x+2;
}
console.log(ReturnUndefinedIfxIsNotAnumberOrFalsy());
//undefined
console.log(ReturnUndefinedIfxIsNotAnumberOrFalsy("x"));
//undefined
console.log(ReturnUndefinedIfxIsNotAnumberOrFalsy(2));
//4