Minzhao Liu

java notes

Eclips

  • C-1 : quick fix

Java

  • // as comment
  • confirm("fisf")
  • prompt("What is your name?"), var = prompt("jkjk")
  • false , 5>3
  • comparison, ===, >= ,
  • logic: not: !, or ||

  • condition

    if (100<2) 
        {
        statement
    }
    else if 
    {
        fds
    }
    else
    {
        statement
    }

String

"word".substring(x,y)
"fdsaf" + "fsdjkfj"
"AAA".toLowerCase()

Variable

var varName = data type;

Loop

for (var counter = 1; coutner <=5 ; counter=counter+1)
{
	statement;
}
counter ++ 
counter +=1

while (condition) {
	statement;
}

loop in obj

for(var property in dog) {
console.log(property);
}

dog[prperty];

Functions

var hello=function() {
	return x;
};

Array

var lost=[1,3,4]

start from 0

Switch

switch (jacketColor) {

case "black":
 result = "Pay $300";
break;

case "brown":
  result = "Pay $200";  
break;

case "green":
  result = "Pay $5";
break;

default:
 result = "This color does not match my eyes!";
 }

ifelse

result = x > y ? "good job" : 20;

Math

Math.random()
Math.floor()
Math.max()
Math.PI

Object

var obj={
  age:22,
  fdsfa: fsf,
  speak: function(){
  }
}

obj.age
obj["age"]

var obj= new Object();
obj.age=24;

can pass objects into functions

Method

obj.setAge = function(pa){};

this

var setAge=function(x){
	this.age=x;
}
bob.setAge=setAge;

Prototype

teach all objects methods:

className.prototype.newMethod = function() {
statements; 
this.name;
};

Inherit

Penguin.prototype = new Animal();

New construct

function Person(name, age){
	this.name=name;
	this.age=age;
	this.species="d";
	this.calcArea=function(){
		return this.length*this.width;
	};
}
var bob=new Person("bos", 27);

Array of objects

var family=new Array();
family[0]= new Person("""");

function

typeof something;

obj method:

obj.hasOwnProperty("name");

Privacy

function Person(first,last,age) {
var bankBalance=7500;  # private

  this.getBalance = function() {
  // your code should return the bankBalance
  
}; # public method

var returnBalance=function(){} ;# private method

}

Q

  • what is JRE

Published

07 August 2012

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