Function pointers point to the address of the executable code of the function. You can use pointers to call functions and to pass functions as arguments to other functions.

Core concepts of OOP(Object-oriented programming): abstraction, encapsulation, inheritance and polymorphism.

Array.prototype.includes(target) determines whether an array includes a certain element, returning True or False as appropriate.

f(), ff()and console.log('a') will be push in the call stack one by one and be popped out in the reverse order (first in last out).

Based on p5.js examples.Click here for the differences between p5.js and processing.Check out p5.js references for more information.