Intro to Java; Info & Math in Java

Question 1

how does software work?

Answer 1

u boot the PC & it starts reading instruction from the storage device

the bytes r interpreted as instructions by the PC

the instructions = software –> created thru the process of programming

Question 2

programming

Answer 2

giving sequential instructions to a computer system

done using a programming language

Question 3

programming language

Answer 3

turned into instructions for a CPU by a compiler

series of rules that u follow to write English-like text representing abstract instructions

Ex: Java

Question 4

compiler

Answer 4

a translator from the programming language instructions to the byte instructions used by the CPU

Question 5

programming constructs

Answer 5

many programming languages have similar capabilites

Question 6

Integrated Development Environment (IDE)

Answer 6

something like BlueJ that combines a text editor with a compiler

Question 7

code

Answer 7

the text of a program

Question 8

Java’s naming rules

Answer 8

starts with letter

can contain letters, #’s, $, and _

no spaces

case sensitive

Question 9

sample print statement

Answer 9

public class CompSci {

public static void main (String [] args)

{

      System.out.println("Hello World!");

}

}

Question 10

whitespace

Answer 10

spaces, tabs, etc.

Question 11

values & types

Answer 11

Java & all other programming languages have diff types of info

Ex: strings, integers, doubles, and Booleans

Question 12

strings

Answer 12

look like text inside of a pair of quotation marks

Question 13

integers

Answer 13

same thing as integers in math - whole #’s with no decimal point

Question 14

doubles/floating-point values

Answer 14

what we might call real #’s in math - #’s that have a decimal point

Question 15

Booleans

Answer 15

only 2 values: true and false

in Java, the words true and false (lowercase) r reserved for Boolean values

Question 16

operators

Answer 16

the symbols that we use to perform calculations on diff values

Question 17

arithmetic operators

Answer 17

+, -, *, /, %

paranthesis used same as in math

Question 18

concatenation/catting

Answer 18

if u “add” anything to a string, it will stick the value onto the string

must be adding

Ex: “Hello” + “werld” = “Hellowerld”

50 + “8” = “508”

“Zoobah” + 0.5 * 3 = “Zoobah1.5”

Question 19

integer division

Answer 19

when 2 integers r divided, the result is always an integer

Java will not round - will simply cut off

Ex: 6/4 = 1

2/3 = 0

if either of the values being divided is a double, then Java will do normal division

Ex: 1/5.0 = 0.2

Question 20

Modulus Division

Answer 20

only works on integers

gives remainder of 1st # dvided by the 2nd #

Ex: 6%4 = 1R2 = 2

12%3 = 4R0 = 0

If the 1st # is less than the 2nd #, then the answer is always just the 1st #

Ex: 3%4 = 3