Tasks

7.1 How Code and Variables Work in Memory

• If you have access to actual hardware pieces, use the hard drive and RAM chips as references.
• RAM is like a cupboard full of shelves
• Each shelf has a specific address
• Creating a variable names a shelf
• Some languages (but not ours) have TYPES of variables. This makes memory management more efficient but makes coding more complex.
• When you reference a name of a variable, it is going to see what is in that shelf:
  • let x; //this names the shelf in memory x;
  • x = 15; //fills the shelf with the number 15
  • print(x); //gets whatever is in shelf x
  • x = x + 10; // gets what is in shelf x, adds 10 to that number, resaves it in shelf x
  • if (x===25){ } // checks to see what is in shelf x

7.2 Variables Example - Ticket Sales

• Before beginning, talk about empty variables. Demo the error if you try to print an empty variable and print an empty variable with math.
  • let empty1;
  • let empty2;
  • function draw() {
  • text (empty1, 50,50);
  • text ((empty2*5), 50,50);
  • }
• Introduces window.prompt()

7.3 Discuss the Following AP Concepts

• AAP-1.A.1: A variable is an abstraction inside a program that can hold a value. Each variable has associated data storage that represents one value at a time, but that value can be a list or other collection that in turn contains multiple values. 
• AAP-1.A.2: Using meaningful variable names helps with the readability of program code and understanding of what values are represented by the variables.
• AAP-1.A.3: Some programming languages provide types to represent data, which are referenced using variables. These types include numbers, Booleans, lists, and strings. 
• AAP-1.A.4: Some values are better suited to representation using one type of data rather than another. 
• AAP-1.A.4: Some values are better suited to representation using one type of data rather than another. 
• AAP-1.B.2: The exam reference sheet provides the “←” operator to use for assignment. 
• AAP-1.B.3: The value stored in a variable will be the most recent value assigned.

Continue to Unit 1: Day 8 »