Section 1
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do while loop syntax
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Date created
Mar 1, 2020
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Section 1
(50 cards)
do while loop syntax
do { // Loop body; Statement(s); } while (loop-continuation-condition);
(x % n == 0)
number x is divisible by n
main method
method called by JVM to start a program
conditional expression syntax
boolean-expression ? expression1 : expression2; The result of this conditional expression is expression1 if boolean-expression is true; otherwise the result is expression2.
comparison operator
=relational op., mathematical operators to compare:
loop
a programming construct that repeats a group of commands.
pretest loops
check before the action (for and while loops); they may never act
for loop syntax
for (initial-action; loop-continuation-condition; action-after-each-iteration) { // Loop body; Statement(s); } (If the loop-continuation-condition in a for loop is omitted, it is implicitly true, therefore infinite- while loop would be more efficient)
else if
used to simplify multiple nested alternatives
Main Method Syntax
Public static void main(String[] args) { // code }
continue statement
breaks up the current iteration of a loop if a certain condition is fulfilled, use it to e.g. exclude certain cases from being included from the execution of a for loop body
(formal) parameters
variables defined in the method header (need to be defined separately)
do-while loop
like while loop, but executes the loop body before checking the continuation condition (use when statements must appear at least once before the loop kicks in)
goto statement
a statement that transfers control to some other statement, which is tagged with a label. Java does not have a goto statement.
actual parameter (argument)
value associated with the parameter when method is invoked
ambiguous invocation
If the compiler finds two or more methods that equally match a given call, it will issue an error
sentinel value
a preselected value that stops the execution of a program (doesn't work with floating point values)*
posttest loop
a loop whose condition is evaluated after the instructions in its loop body are processed
conditional expression
way to assign a value to a variable under a certain condition
method overloading
When multiple methods have the same name, but different parameters. (preferred method style since it makes program more readable and clearer)
class
A class is a template, blue- print, or contract that defines what an object's data fields and methods will be, one class can have multiple objects
value-returning method
A method that returns a value(, it's body requires a return statement)
local variable
a variable that is declared within a method, must be given a value before it's used and can't be used outside that method(=block of code) e.g. a parameter (can't be declared twice)
object
represents an entity in the real world that can be distinctly identified e.g. a circle through its: 1.state=data fields (defined by variables) e.g. radius 2.behavior=methods e.g. getPerimeter() also known as an instance of a class
pass-by-value
Passing the value of an argument to a method. The type of data passed depends on whether the argument is a primitive or an object. (memory allocation for argument and parameter is independent)
modularizing code
making it more efficient*
graphical user interface (=GUI)
%
modulus operator; divides two integers and returns the remainder as an integer
invoking a method from another class (in the package)
call: className.methodName
method syntax
modifier returnValueType methodName (parameters){ body= statements }
method abstraction
Achieved by separating the use of a method from its implementation, where method body=black box aka. hidden from user
switch statement syntax?
switch ([control expression]) { case [integer type (char works) that may be equal to control expression]: [Stuff to do with control expression varable]; break; default: [stuff to do if none of the cases equal the control] } *you can also stack cases example: switch(letter) { case 'a': case 'e': case 'i': case 'o': case 'u': isVowel = true; break; default : isVowel = false; break: }
method signature
The name of a method, along with its number and type of parameters, it's used to invoke a method
while loop
construct used to repeat a set of commands (loop) as long as (while) a boolean condition is true (braces enclosing the loop body can be omitted only if the loop body contains one or no statement.) (used for infinity loops or true or false boolean condtions)
for loop
standard loop, used if the number of desired iterations is known
parameter order association
arguments must be given in the same order as the formal parameters to call method correctly
Calling a Value-Returning Method
call is treated as a value, either in print statement or in the declaration of a variable
selection statement
=conditional statement, .allows us to choose which statement will be executed next based on the evaluation of a boolean condition. e.g. if, if...else, else...
switch statement
allows multi-way branching. In many cases, using a switch statement can simplify a complex combination of if-else statements.
Boolean data type
allows you to create variables that may hold one of two possible values: "true" or "false"
if-else statement
allows your program to perform one action if the Boolean expression evaluates to true and a different action if the Boolean expression evaluates to false, therefore if statement that always operates
End-of-line Block Style
starting the braces right after the parameter list of a method instead of in the next line
counter-controlled loop
a loop whose processing is controlled by a counter; the loop body will be processed a precise number of times
if statement
A statement that determines whether or not you run a certain chunk of code, and therefore allows for alternate paths of execution
while loop syntax
while (condition)//initialise a counter variable before the loop { statement(s);//one of the statements must be an increment otherwise loop is infinite }
constructor
a method mainly for creating objects (using the new operator), by initializing their variables
break statement
A statement that terminates a loop or switch statement.
Calling void methods
call requires a statement*
Method
series of statements grouped together to perform an operation, way to make code reusable
void method
A method with void in place of the return type, which does not return a value when called
Section 2
(50 cards)