Thursday, January 23rd

Section 4: Lesson 3 - Data Types and Operators

ScopeExample - create a class called ScopeExample and copy the code.  

Scope (lifespan) of a Variable - very important concept
1. Scope of a parameter ( the value passed into a method) - only in the body of the method
2. Scope of a local variable - only within the block of code where it was declared
3. Scope of a local variable in a for loop - only in the for loop
* if you want the variable to be accessible after the loop then declare it before the for loop
4. Scope of a method or field of a class - anywhere in the class - class scope
Scope Tutorial

Section 4: Lesson 3 - Data Types and Operators Vocabulary:
- Named primitive or object storage mechanisms defined in a program. The assigned value may or may not (constants) change.
- Symbols are used to do addition, subtraction, multiplication, division, and modular arithmetic in math expressions and formulas.
- The group of Java data types that do not use the keyword new when declared or initialized. Primitive Data Types store the value in the same place in memory as the variable name.
- The smallest java primitive type (1 byte) that can hold an integer value.
- This data type (8 bytes) is the largest integer type.
- The formatting and naming standards that most programmers follow.
- This Java primitive data type (4 bytes) can hold integer values.
- This Java primitive data type (8 bytes) is the largest primitive that can hold a decimal value.
- When a variable is assigned a value for the first time.
- This Java primitive data type (4 bytes) can be initialized with a decimal number preceding letter f. Example: float x = 3.5f;
- Can be any number, text, or other information that represents a value; used to initialize a primitive type.
- A Java statement when a variable is defined but not necessarily assigned a value. Example: int x;
- This word describes the mathematical precedence that a variable has in a Java program.
- A java primitive data type (2 bytes) that can hold single character values. Example: “a”, “#”, or “X”
- Used to describe the block of code where a variable exists in a program. A block of code is denoted by {}.
- The process of explicitly modifying one data type to become a different data type.
- A concept where a number is always rounded down to the nearest integer.
- The equals sign “=” used in a Java statement to assign a value to a variable.
- The process of modifying one data type to become a different data type, this may be implicit or explicit.
- A Java primitive data type (2 bytes) that holds integer numbers within a shorter range than an int. - A one-bit java primitive type that can hold the value true or false.

Review - primitive data types, variableNames, declaring and initializing variables, variable scope

0b0101, 0x56AC, 56.304f

Operator Precedence + - / * % ++ --
How can you override precedence?
Modulus operator %
Pre-increment vs Post-increment
implicit type conversions - smaller into bigger is OK but the reverse is NOT allowed.
Using the Java API (or Google)
Relational Operators
Logical Operators

Complete Section 4 Lesson 3: Data Types and Operators slides
Complete Section 4 Lesson 3: Data Types and Operators practice
Show me your TriangleArea calculator - prob #1, FieldTrip calculator - prob #3, and the rest of the questions. The math calculations - prob #2 is extra credit.
The final output for the Triangle Area should look like this: The area of a triangle with a base of ____ and a height of ___ is _____. Thank you for using the Triangle Area Calculator. This program is brought to you by

The final output for the Field Trip program should look like this:Your field trip with ______people will require ______busses and _____ vans. Thanks for using the field trip calculator. This program was brought to you by

For the MathPractice problem use the following values for the variables for A-C
double x = 3.0;
double y = 5.0;
double z = 4.0;
double answer = 0.0;
For problems D-F make y=2.0 Your output should show the following for each problem:
Problem A.
X = 3.0 - show the actual values of all variables used in the formula, in this case only X
The answer is 3.848701079585163

Homework

Install Eclipse on your home computer if you would like to be able to work on your java at home.

What

In this lesson, you will learn how to:
• Create a WHILE loop
• Create a DO-WHILE loop
• Input characters from the keyboard during program execution
• Use the full form of the IF statements and FOR loops
• Apply switch in Java code
• Use break effectively in Java code
• Rewrite a Java program to prompt the user for input and perform a mathematical calculation

Why

When creating code that needs to execute logic more than once, loops become a very useful tool.
Loops are central to programming and primarily work to change the flow of a program similar to conditional statements like IF and ELSE.
Loops help you simplify your code while allowing you the flexibility to repeat code execution with ease.

How

By completing the slides, quiz and practice exercises.