1// (param1, param2, paramN) => expression
2
3// ES5
4var multiplyES5 = function(x, y) {
5  return x * y;
6};
7
8// ES6
9const multiplyES6 = (x, y) => { return x * y };
10

1//Anonymous function; It's not assigned to an indentifier
2
3Array.forEach((arguments) => {
4	//This is an anonymous function
5})
6
7function forEach(arguments) {
8	//This is NOT an anonymous function
9}
10

1// Arrow functions
2// ES6 introduced arrow function expression that provides a shorthand for declaring anonymous functions:
3
4// For example, this function:
5
6let show = function () {
7    console.log('Anonymous function');
8};
9// Code language: JavaScript (javascript)
10// … can be shortened using the following arrow function:
11
12let show = () => console.log('Anonymous function');
13let show = (variable) => { /* code */ }
14// Code language: JavaScript (javascript)
15// Similarly, the following anonymous function:
16
17let add = function (a, b) {
18    return a + b;
19};
20// Code language: JavaScript (javascript)
21// … is equivalent to the following arrow function:
22
23let add = (a, b)  => a + b;   

1// Regular function, called explicitly by name .aka “named function”
2function multiply(a, b){
3	var result = a * b; 
4	console.log(result);
5} 
6multiply(5, 3);
7
8// Anonymous function stored in variable. 
9// Invoked by calling the variable as a function
10// Anonymous functions don't have a name, 
11// so the parentheses appears right after “function” keyword.
12var divided = function() {
13	var result = 15 / 3;
14	console.log("15 divided by 4 is "  + result);
15}
16divided();
17
18// Immediately Invoked Function Expression.
19// Immediately invoked function expressions are anonymous functions 
20// with another parentheses pair at the end to trigger them, 
21// all wrapped inside parentheses.
22// Runs as soon as the browser finds it: 
23(function() {
24	var result = 20 / 10;
25	console.log("20 divided by 10 is " + result);
26}())
27

1 1 int function (int a) {
2 2   return a + 3;
3 3 }
4 4 
5 5 class Functor {
6 6   public:
7 7     int operator()(int a) {
8 8       return a + 3;
9 9     }
1010 };
1111 
1212 int main() {
1313   auto lambda = [] (int a) { return a + 3; };
1414 
1515   Functor functor;
1616 
1717   volatile int y1 = function(5);
1818   volatile int y2 = functor(5);
1919   volatile int y3 = lambda(5);
2020 
2121   return 0;
2222 }
23