Chapter 1

Computer

A machine that stores and processes data

Hardware

Physical components of a computer

Software

Part of the computer, unseen instructions that control the hardware and processes

What is a solid-state drive?

Part of computer that uses flash memory to store files and other data. Part of storage.

What is RAM?

Part of computer that holds data read from storage

Processor

Part of computer that:

runs the computer’s programs

reads and executes instructions from memory

performs operations

Clock

governs the rate at which a process executes instructions, ticks at a specific frequency

What are the three basic instruction types?

Input, process, output

Input

program receives data (from file, keyboard, etc.)

Process

program performs computations on that data

Output

A program puts that data somewhere

Program

Created sequence of instructions

Machine language/instructions

instructions represented as 0s and 1s

Executable program

Sequence of machine instructions together

Assembly language

human readable instructions of machine instruction, low-level language that can be translated into the machine language

High-level languages

Programming using formulas or algorithms resembling written languages

ex. Java itself

Compilers

programs that automatically translate high-level language programs into executable programs

Object

real-world entity brought to life in code

What is the first step in translating high-level language?

Source code is stored on a disk in a file with a name ending in .java (source file). This has instructions written in high-level language.

What is the second step in translating high-level language?

Compiler creates bytecode that is stored on a disk in a file with a name ending in .class.

What is the third step in translating high-level language?

Java Virtual Machine (JVM) (named java.exe) performs security checks and translates bytecode to machine language, which executes

What are the stages of a code when running a program?

Java code file

Java bytecode

Machine language

Program runs on hardware

Syntax

A specific set of rules for the language

Program statements

Commands to carry out program tasks

Syntax error

Misuse of language rules, a misspelled programming language word

Debugging

Attempting to free programs of all errors

Logic error

When there is an incorrect order or procedure, compiles but not run as intended.

Class

Describes objects with common properties, a blueprint for objects

What do programs begin with?

public class NAME

For public class NAME, what does the NAME have to match?

match the name of the file

What is the second statement put into programs?

public static void main(String[] args)

What is a literal string?

Will appear in output exactly as entered, written between double quotation marks

What is an argument?

The actual value or data that you pass into a method

ex. addNumbers(5, 10); (5 and 10 are the arguments)

What is a method?

A structured, reusable block of code that groups together a sequence of statements to perform a specific task

What are method names always followed by?

Parentheses ()

What do classes always start with?

A capital letter

What can identifiers not begin with?

Cannot begin with a digit

What can identifiers not contain?

Java reserved keywords

What is public?

An access specifier meaning it is available to all other entities

What is whitespace?

Space and tabs between items within a statement and blank lines between statements

What is static?

a reserved keyword, means the method is accessible and usable even though no objects of the class exist

What is void?

Indicates the main() method does not return a value when called

What command compiles the program?

javac

What is a compile-time error?

The compiler detects a violation of languag erules and refuses to translate the class to machine code

What command interprets the class bytecode and executes the class?

java

What is a logic error?

The syntax is correct but incorrect results were produced when executed

What is a run-time error?

An error that occurs while the program is running, after is has successfully compiled (an illegal or impossible operation)

What are line comments?

Starts with two forward slashes (//), Continue to the end of the current line/ Does not require an ending symbol

What is a block comment?

Starts with (/*) and ends with (*/)

What would a javadoc comment look like?

begins with (/**) and ends with (*/)

What is an IDE?

An integrated development environment which is software that integrates a text editor (writes code) and a compiler

What is a console?

A text-based interface that allows users to run programs, enter input, and view program output

What are statements enclosed in?

curly braces

How many statements should appear on one line?

One

What do statements end with?

Semicolons (;)

What does int ___ do?

Creates a variable name that is an integer data type

What is an integer?

A whole number

Are you able to combine text and values on the same print line?

Yes

How do you combine text and values on a print line?

With a + symbol

ex. (“Wage is “ + wage);

What are blank lines?

An entire space of line between two statements

When are blank lines used?

To separate conceptually distinct statements

When should be indent lines be used?

To indent by the same amount for related lines of codes

If there is a syntax error, which lines should you look at?

At the specified line and if not there at previous lines

What should you do when fixing a long list of errors?

Fix one error first and then compile (it may fix the entire line of errors)

How much does an int hold?

+/ - 2 billion

What is double?

Like int but can use decimals

How do you read binary digits?

Binary digits are 1s and 0s. Read from right to left. The first digit to the right is to be multiplied by 1, the second 2, the third 4, the fourth by 8. It keeps doubling. Then add all of the numbers together