APCSA Unit 1 - Primitive Types

How do you start a java code?

public static void main (String [] args)

What is a statement in java? Give an example.

A complete argument in java. Example: System.out.print(“literal”);

What is a class in Java? Give an example.

A template that associates and creates objects that share common properties and methods. Your public class must match the name of the file with a .java extention. Example: public class MyClass

What is a keyword in Java? Give an example.

A word reserved by java to run code. Example: if, public, and class

How do you make comments in java?

With two slashes (//) or with a slash and an asterisk and a backslash and an asterisk (/**/)

What is a variable?

A name associated with a memory location in the computer where you can create a value to change or vary.

Give an example of how to combine literals and variables and have the computer print both.

System.out.print (“base: “ + base);

Give an example on how to declare a variable only.

int a

Give an example on how to set an initial value for a variable only.

a = 4

Give an example of how to set a variable and give it a variable.

int a = 4

What is an int variable?

Interger (math variable)

What is a double variable?

Decimal (math variable)

What is a String variable?

A variable that includes quotes and string text

What is a boolean variable?

A variable that can only be True or False

How do you find the answer of a decimal problem in decimals in java?

Use the primitive variable double and include decimal points in any number included.

List all the math operators.

+,-,*,/,and %

What are compound operators? List them.

Operators that use two math symbols. -- subtracts one, ++ adds one, a+=2 would set a to a + 2.

What does / do in java?

Divides two numbers and gives an integer answer (no remainder)

What does % do in java?

Gives only the remainder of a division problem.

What are the types of variables?

Primitive and object or reference variables

What are the primitive variable types in java?

int, double, string, boolean

What is the string variable used for?

Secquences of charectes

How many bits does a boolean variable use?

1

What is the string concatenation operator?

+

What does final do in java?

stops a variable from being changed

What is camel case?

When you uppercase the first letter

What is an assign statement?

A statement that changes the value

What is this operator called %?

Modulo

What is 11 % 10 saying?

What is the remainder of how many times 10 goes into 11?

Does the division operator drop the decimal after dividing?

Yes, no rounding

Variable

A name associated with a memory location in the computer.

boolean

used to declare a variable that can only have the value true or false.

double

used to declare a variable that is a decimal number like 3.25.

int

used to declare a variable of type integer (a whole number like -3 or 235).

static

means that the field or method exists in the object that defines the class.

compiler

Software that translates the Java source code into the Java class file that can be run.

compiler or syntax error

An error or bug that is found by the compiler like a missing semicolon

Main Method

Where execution starts in a Java program.

Boolean

An expression that is either true or false.

Camel Case

One way to create a variable name by appending several words together and uppercasing the first letter of each word after the first word (myScore).

Casting a Variable

Changing the type of a variable using (type) name.

System.out.println()

Java method that lets us print out a line of output followed by a newline to the user

Declare a Variable

Specifying the type and name for a variable. This sets aside memory for a variable of that type and associates the name with that memory location.

Initializing a Variable

The first time you set the value of a variable.

String literal

Text enclosed by double quotes.

modulo

The % operator which returns the remainder from one number divide by another.

Operator

Common mathematical symbols such as + for addition and * for multiplication.

Shortcut or compound assignment operators

Operators like x++ or x+= 1 which mean x = x + 1

assignment statements

initialize or change the value stored in a variable using the assignment operator =.

data type

determines the size of memory reserved for a variable, for example int, double, boolean, String.

ArithmeticException

If you divide by zero, you will get this error.

operator precedence

Some operators are done before others, for example *, /, % have precedence over + and -, unless parentheses are used.

arithmetic expression

a sequence of operands and operators that describe a calculation to be performed, for example 3*(2 + x)

increment operator

The operator (++) that increases the value of a numerical variable by one.