Unit 1 (Data Types and Digital Information)

Digital Information and Data Types

Digital Information (bits, bytes, and abstraction)

Other number System (Video on binary, octal, decimal, and hexadecimal numbers)

Complete: PL Computer Science Data Module 1: Lesson 1

Data Types

Numeric Data Types

Type                     What it stores              Storage Requirements                      Range

int                       whole numbers                            4 byte                                            -2,147,483,648 to +2,147,483,647

double                decimal numbers                        8 byte                                             -1.7977+E308 to +1.7977+E308

float                    decimal numbers                        4 byte                                            -1.175494351 E 38 to 3.40282346E38

Non-Numeric Data Types

Type                    What it stores                      Examples

char                        single characters                 ‘s’, ‘$’,’A’

boolean                  logical values                        true, false

Assignment: 

Note that the form of the assignment statement requires that the variable to be assigned is on the left of the equal sign and that the assigning expression is always on the right. See below.

Correct:       age = currentYear - yearBorn;

Incorrect:     currentYear - yearBorn = age;

Assign Values before using:

We can also use declared variables in equations and output, but only after first giving the variable a value.

Correct

double price = 18.95, tax;  

tax = .0725 * price;

Incorrect

double price, tax;

tax = .0725 * price;

The problem in the second version is that we are trying to use the variable price in an equation, but price does not have a value yet. This will produce a compile-time error. The same error will occur if we try to output the price before it has a value.

Basic String Operations:

A String is a “string” of characters which can be a word or several words (including numbers and symbols).  The indices of the characters are numbered from 0 to str.length – 1.

Concatenation:  The process of combining two or more strings with the + operator is called concatenation.

String combination = “Let’s” + “Go”;

println(combination); //prints Let’sGo (no space)

Note: On the GACE it will be notated as print(combination)

Problem Set 1:

    1) Determine an appropriate data type for the following values

• 1. Amount of money in checking account

  2. Whether or not a person voted or not

  3. Your Full Name

  4. The first letter in your name

  5. Number of siblings

  2) Conversions:

• 1. Convert 39 (base 10) to binary

  2. Convert 10101 (base 2) to decimal

  3. Convert 74 (base 8) to decimal

  4. Convert 62 (base 8) to binary

  5. Convert 2A (base 16) to decimal

  6. Convert 39 (base 16) to binary

3) Go over basic methods in Processing.

a) setup, draw, print, operations, order of operations, methods, errors (syntax, run-time, logical)

More Practice with Unit 1 and related concepts: Complete Data Course from GADOE

Before Unit 2: Read over the notes for conditionals, iteration, and recursion in Unit 2.