When one method calls another, which of the following statements are true?

I. The class methods and instance methods of one class may call the public class methods of another class using dot notation and referencing the name of the other class.
II. The class methods and instance methods of one class may call the private instance methods of another class by using dot notation to invoke the method on an instance of the other class.
III. The instance methods of a class may call, without using dot notation, any class method of the same class.

Ihave a music player on my phone. i can buy songs, add them to playlists and play them. obviously it would be redundant to store each song in each playlist; each playlist is just a list of pointers to the songs. for this lab you will simulate this behavior. your program will need to have options to: add songs to the system library (you will store the text of the first line of the song, rather than the audio) add playlists add songs to a playlist list playlists play a playlist list all of the songs in the library with a count of how many times each song has been played remove a song from a playlist remove a playlist remove a song from the library (and thus from all playlists that contain it) note that we will not be checking many error cases. in real programming this would be bad, you should usually try to recognize and respond to as many types of errors as you can. in the context of class we are trying to acquaint you with as many concepts as possible, so for the sake of educational efficiency we will not be checking most errors in this lab, you may assume that your user provides correct input. you may add all appropriate error testing if you wish, but we will not be testing for it.

What statement best describes operating systems? it’s possible for modern computers to function without operating systems. most operating systems are free or very inexpensive. operating systems are managed by the computer’s microprocessor (cpu). operating systems manage the computer’s random access memory (ram).

Least square fit to polynomial write a function leastsquarefit3pol that solves a linear system of equations to find a least squares fit of a third order polynomial to an experimental data set given as two row arrays. the function leastsquarefit3pol must explicitly solve a set of linear equations and cannot use polyfit. there should be no restriction on the size of the problem that can be solved.