Data TypesString | " type string here " | int | E.G: 0 | boolean | true/false | char | 'x' | double | E.G 0.00 |
Operators (Summary)+ | Addition / String concatenation | % | Modulus (remainder) | ++ , -- | Increment / Decrement by 1 | ! | Inverts boolean value | = , == | Assigns, Equals to | != | Does Not equal to | >= | Greater than OR Equal to | <= | Lesser than OR Equal to | && | Conditional - AND | || | Conditional - OR |
MethodsSystem.out.println(line) | System.out.printf(format, arguments) | Helper.readDataType(string) |
// For printf formatting //
%d = integer
%s = String
%f = double (.2f = 2dp)
%b = boolean Loops / Impt Statementswhile(condition) | (option != 4) { code } | for(var,cond,incre) | (int 1=0;i<10;i++) | if / else if / else | if(condition) { code } | switch(Expression) | switch (choice) |
Switch syntax: E.g: Input is an int Choice
Switch (choice)
{
case 1:
< code >
break;
.....
default:
< code >
break;
} | | ArraysDeclaring an Array
Syntax:
Datatype[ ] nameOfArray =
new Datatype[ No. of elements in array ];
Example:
int [ ] randomValues = new int [ 7 ];
// Creates an array called randomValues with 7 elements (0-6)
Assigning Value to Array: (Using prev E.G)
randomValues[3] = 100;
// Assigns value of 100 to the 4th element [3] of randomValues array
Declaring & Initializing @ Same Time
int[ ] randomValues = {5,12,51,23,12,24,21};
// Creates an array called randomValues and assigning 7 elements in it in a single line.
Accessing Elements:
System.out.println(randomValue[3]);
// Prints out "23" (prev example)
Finding out Array Length
System.out.println(randomValue.length);
// Prints out 7 |
Values for Primitive Arraysint | 0 | double | 0.0 | boolean | false | String | null |
String MethodscharAt(index) | Returns char @ index | endsWith(suffix) | if ends w suffix | equalsIgnoreCase(string) | length() | Returns length of string | startsWith(prefix) | if starts w prefix | toUpperCase() | Converts to upperCase | toLowerCase() | Converts to lowerCase |
| | Class Diagram'+' = Public , '-' = Private
underlined = Static
// Constructors have the same name as class.
// if return type is 'void' , no return statement is required. Creation of Class// Using the Class Diagram above //
Declare Fields First:
public String licenseNo, colour;
public int speed;
Constructor
[Right-click, Source, Create constructor using Fields, delete the super(); ]
Create Methods:
public void accelerate(int acc)
{
}
public void honk ()
{
} |
// Creating Array/ Object in Main Class //
Array:
Syntax:
ClassName[ ]arrayName = new ClassName[x];
E.g:
Car[ ] testArray = new Car[5]
Objects
E.g:
Car newObject = new Car();
// Creates a new object, called 'newObject'.
Calling a method in Main class from another class
newObject.methodName(); |
Created By
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