fundamentals of electrodynamics

[] args)throwsIOException { - //Encapsulating Data Sources -BufferedReader br =NewBufferedReader (NewFileReader ("B.txt")); - // Encapsulate Destination (Create collection Object) -arraylistNewArraylist(); - in //read data stored in the collection -String line =NULL; to while(line = Br.readline ())! =NULL) { + Array.add (line); - } the * //Freeing Resources $ br.close ();Panax Notoginseng - //iterating through the collection the

{ + //Encapsulating Data Sources -InputStreamReader ISR =NewInputStreamReader (NewFileInputStream ( +"A.txt")); A //Package Destination atOutputStreamWriter OSW =NewOutputStreamWriter (NewFileOutputStream ( -"B.txt")); - - //Read and write Data - //Mode 1 - //int ch = 0; in //While ((ch = isr.read ())! =-1) { - //osw.write (CH); to // } + - //Mode 2 the Char[] CHS =New Char[1024]; * intLen = 0; $

Mylinenumberreadertest, as follows:1 Packagecn.itcast_09;2 3 ImportJava.io.FileReader;4 Importjava.io.IOException;5 6 Public classMylinenumberreadertest {7 Public Static voidMain (string[] args)throwsIOException {8 //Mylinenumberreader MLNR = new Mylinenumberreader (New FileReader (9 //"My.txt"));Ten OneMyLineNumberReader2 MLNR =NewMyLineNumberReader2 (NewFileReader ( A"My.txt")); - - //Mlnr.setlinenumber (ten); the - //System.out.println (Mlnr.getlinen

[] array name; B: Data type array name []; Recommendation is a way, B method forget it. But to be able to read (4) Initialization of an array A: Dynamic initialization gives only the length, the system gives the default value example: int[] arr = new INT[3]; B: Static initialization of the given value, the system determines the length example: int[] arr = new int[]{1,2,3}; Simplified version: int[] arr = {£ º}; (5) Java memory allocation

, the cost is greatly reduced, and reduce the occurrence of bugs2) decomposition of the processFor example, to make a steamed bread, his steps are: face, seasoning, cooking and other steps, each step we can be defined as a function, and then do a steamed bread is required to function is the one-way, and so on, each small step to execute the correct rate is higher than the overall operation.In summary, this section notes why you need to write a function, mainly because it provides efficiency and

Switch statements in Java:Here expression control expressions can only have data types of byte, short, char, int four integer types and enumeration types, and cannot be of type Boolean;Java7 (1.7) improved the Switch Branch statement;Java7 allows the control expression in the switch statement to be of type java.lang.String ( cannot be stringbuffer or StringBuilder)Switch (expression){Case Condition1:{statement (s);Break}Case Condition2:{statement (s);Break}Case Condition3:{statement (s);Break}..

(); atSystem.out.println ("sub.filed =" + Sub.field + -", Sub.getfield () =" + Sub.getfield () + -", Sub.getsuperfield () =" +Sub.getsuperfield ()); - } -}Output:sup.filed = 0, Sup.getfield () = 1sub.filed = 1, Sub.getfield () = 1, Sub.getsuperfield () = 0Analysis:The sub subclass actually contains two fields called field, whereas the default domain generated when referencing field in sub is not a super version of the Field field, so in order to get Super.field, you must explicitly indicate

= List.iterator ();//While (It.hasnext ()) {//string str = (string) it.next ();//if (str.equals ("Polo")) {//List.add ("Pony");// }// }Listiterator listit=List.listiterator (); while(Listit.hasnext ()) {String str=(String) listit.next (); if(Str.equals ("Polo") {Listit.add ("Pony"); } if(Str.equals ("Shery") {Listit.add ("Keity"); }} System.out.println (list); for(inti = 0; I ){ if(List.get (i). Equals ("Polo")) {List.add ("Pony"); } i

After the transformation, began to enter the learning time, the following is the collation of learning notes C # and Java some differences between1, = = and equalsIn C #, the comparison of strings can be = = to compare, but in java use = = has always been false, originally in Java = = is used to see whether two references to the same memory address, equals is the value of the comparison object is equal, the total known string is the reference type of the2, switch the differenceIn C #, after the

Public StaticDate stringtodate (string s, string format) the throwsParseException { + return NewSimpleDateFormat (format). Parse (s); - } $}2. Dateutildemo. Java, as follows:1 Packagecn.itcast_04;2 3 Importjava.text.ParseException;4 Importjava.util.Date;5 6 /*7 * Test of Tool class8 */9 Public classDateutildemo {Ten Public Static voidMain (string[] args)throwsParseException { OneDate d =NewDate (); A //YYYY-MM-DD HH:mm:ss -String s = dateutil.datetos

1. The origin of the collection:We are learning object-oriented language, and object-oriented language is the description of things through objects, in order to facilitate the operation of multiple objects, we have to store these multiple objects. To store multiple objects, you cannot be a basic variable, but rather a variable of a container type, what are the container types in the knowledge we have learned? Arrays and StringBuffer. But what? The result of StringBuffer is a string that does not

(' A ')); -System.out.println ("isdigit:" + character.isdigit (' a ')); -System.out.println ("isdigit:" + character.isdigit (' 0 '))); -System.out.println ("-----------------------------------------"); - //Public Static char touppercase (char ch): Converts the given character to uppercase characters -System.out.println ("toUpperCase:" + character.touppercase (' A ')); inSystem.out.println ("toUpperCase:" + character.touppercase (' a ')); -System.out.println ("---------------------------

multiplicand) A * Public BigDecimal Divide (BigDecimal divisor) - * Public BigDecimal Divide (BigDecimal divisor,int scale,int roundingmode): quotient, several decimals, how to take out - */ the Public classBigdecimaldemo { - Public Static voidMain (string[] args) { - //System.out.println (0.09 + 0.01); - //System.out.println (1.0-0.32); + //System.out.println (1.015 *); - //System.out.println (1.301/100); + ABigDecimal BD1 =NewBigDecimal ("0.09"); atBigD

long - * Float float - * Double double the * Char Character - * Boolean boolean - * - * Used for conversions between basic data types and strings. + */ - Public classIntegerdemo { + Public Static voidMain (string[] args) { A //No, the trouble is coming. at //Public static String tobinarystring (int i) -System.out.println (integer.tobinarystring (100)); - //Public static String tooctalstring (int i) -System.out.println (integer.tooctalstring (100)); -

= new float (F1);Double D1 = F1.doublevalue ();e.g: double--->intDouble D1 = 100.00;Double D1 = new double (d1);int i1 = D1.intvalue ();(6) Conversion of string types to other data typesClass Test {public static void Main (String args[]) {int i1 = 10;float f1 = 3.14f;Double D1 = 3.1415926;Integer I1 = new Integer (i1);float F1 = new float (F1);Double D1 = new double (d1);String SI1 = i1.tostring ();String sf1 = F1 . toString ();String SD1 = D1. toString ();System.out.println ("SI1" +SI1);System

responsible for accepting user input, and informs the second class object (Checkerboard object) The change of the chess piece layout, the Checkerboard object receives the change of the chess piece to be responsible to show this change on the screen, and uses the third kind of object (rule system) to decide the chess game.For a novice, want to put the object-oriented thinking in the development of the use of the easy, is not a simple thing, has been said object-oriented is a kind of thought, tha

immediately but may be satisfied at some point in the future, and these four forms are handled differently: the first is to throw an exception, and the second is to return a special value (null or false, depending on the operation), the third is to block the current thread indefinitely until the operation succeeds, and the fourth is to block only within the given maximum time limit before discarding. These methods are summarized in the following table: Throw except

("StartsWith:" + s1.startswith ("H")); ASystem.out.println ("StartsWith:" + s1.startswith ("Hello")); theSystem.out.println ("StartsWith:" + S1.startswith ("World"))); +System.out.println ("-----------------------"); - $ //Exercise: Boolean endsWith (String str): Determines whether a string ends with a specified string. $ - //boolean isEmpty (): Determines whether the string is empty. -System.out.println ("IsEmpty:" +s1.isempty ()); the -String S4 = "";WuyiString S5 =NULL; t

2x3=6 2x4=8 2x5=10 2x6=12 2x7=14 2x8=16 2x9=183x1=3 3x2=6 3x3=9 3x4=12 3x5=15 3x6=18 3x7=21 3x8=24 3x9=274x1=4 4x2=8 4x3=12 4x4=16 4x5=20 4x6=24 4x7=28 4x8=32 4x9=365x1=5 5x2=10 5x3=15 5x4=20 5x5=25 5x6=30 5x7=35 5x8=40 5x9=456x1=6 6x2=12 6x3=18 6x4=24 6x5=30 6x6=36 6x7=42 6x8=48 6x9=547x1=7 7x2=14 7x3=21 7x4=28 7x5=35 7x6=42 7x7=49 7x8=56 7x9=638x1=8 8x2=16 8x3=24 8x4=32 8x5=40 8x6=48 8x7=56 8x8=64 8x9=729x1=9 9x2=18 9x3=27 9x4=36 9x5=45 9x6=54 9x7=63 9x8=72 9x9=813. Output graphics Packagetes

(); - //System.out.println ("Age is:" + i); - - //ot.setobj (New String ("Brigitte")); + // //classcastexception - //Integer II = (integer) ot.getobj (); + //System.out.println ("name is:" + II); A atSystem.out.println ("-------------"); - -objecttoolNewObjecttool(); - //ot.setobj (new Integer);//This is the time to compile . -Ot.setobj (NewString ("Brigitte")); -String s =ot.getobj (); inSystem.out.println ("name is:" +s); - toObjecttoolNewOb