3. Essential Java Classes. 1. Strings - презентация, доклад, проект скачать

Нажмите для полного просмотра!

3. Essential Java Classes. 1. Strings, слайд №1

3. Essential Java Classes. 1. Strings, слайд №2

3. Essential Java Classes. 1. Strings, слайд №3

3. Essential Java Classes. 1. Strings, слайд №4

3. Essential Java Classes. 1. Strings, слайд №5

3. Essential Java Classes. 1. Strings, слайд №6

3. Essential Java Classes. 1. Strings, слайд №7

3. Essential Java Classes. 1. Strings, слайд №8

3. Essential Java Classes. 1. Strings, слайд №9

3. Essential Java Classes. 1. Strings, слайд №10

3. Essential Java Classes. 1. Strings, слайд №11

3. Essential Java Classes. 1. Strings, слайд №12

3. Essential Java Classes. 1. Strings, слайд №13

3. Essential Java Classes. 1. Strings, слайд №14

3. Essential Java Classes. 1. Strings, слайд №15

3. Essential Java Classes. 1. Strings, слайд №16

3. Essential Java Classes. 1. Strings, слайд №17

3. Essential Java Classes. 1. Strings, слайд №18

3. Essential Java Classes. 1. Strings, слайд №19

3. Essential Java Classes. 1. Strings, слайд №20

3. Essential Java Classes. 1. Strings, слайд №21

3. Essential Java Classes. 1. Strings, слайд №22

3. Essential Java Classes. 1. Strings, слайд №23

3. Essential Java Classes. 1. Strings, слайд №24

3. Essential Java Classes. 1. Strings, слайд №25

3. Essential Java Classes. 1. Strings, слайд №26

3. Essential Java Classes. 1. Strings, слайд №27

3. Essential Java Classes. 1. Strings, слайд №28

3. Essential Java Classes. 1. Strings, слайд №29

3. Essential Java Classes. 1. Strings, слайд №30

3. Essential Java Classes. 1. Strings, слайд №31

3. Essential Java Classes. 1. Strings, слайд №32

3. Essential Java Classes. 1. Strings, слайд №33

3. Essential Java Classes. 1. Strings, слайд №34

3. Essential Java Classes. 1. Strings, слайд №35

3. Essential Java Classes. 1. Strings, слайд №36

3. Essential Java Classes. 1. Strings, слайд №37

3. Essential Java Classes. 1. Strings, слайд №38

Содержание ▲

Вы можете ознакомиться и скачать презентацию на тему 3. Essential Java Classes. 1. Strings. Доклад-сообщение содержит 38 слайдов. Презентации для любого класса можно скачать бесплатно. Если материал и наш сайт презентаций Mypresentation Вам понравились – поделитесь им с друзьями с помощью социальных кнопок и добавьте в закладки в своем браузере.

Слайды и текст этой презентации

Слайд 1

Описание слайда:

3. Essential Java Classes 1. Strings

Слайд 2

Описание слайда:

Strings Strings are a sequence of characters. In the Java strings are objects. The simplest way to create a string String greeting = "Hello world!";

Слайд 3

Описание слайда:

String Length String palindrome = "А роза упала на лапу Азора"; int len = palindrome.length();

Слайд 4

Описание слайда:

Concatenation and addition int a = 5; int b = 3; String S = "-output-"; System.out.println (S + a + b); System.out.println (a + b + S); What will be the output?

Слайд 5

Описание слайда:

Converting Numbers to Strings The simplest way: String s = "" + 6; Another way: String tp = String.valueOf(18.3); Formatting: String mes = String.format("Result = %d", 25);

Слайд 6

Описание слайда:

Strings Comparing (1 of 3) String s1 = "hello"; String s2 = "hello"; if (s1 == s2) System.out.println(“Equal”); else System.out.println(“Not equal”); What will be the output?

Слайд 7

Описание слайда:

Strings Comparing (2 of 3) String s1 = "hello"; String s2 = new String("hello“); if (s1 == s2) System.out.println(“Equal”); else System.out.println(“Not equal”); What will be the output?

Слайд 8

Описание слайда:

Strings Comparing (3 of 3) You should use equals method instead of == String s1 = "hello"; String s2 = new String("hello“); if (s1.equals(s2)) System.out.println(“Equal”); else System.out.println(“Not equal”);

Слайд 9

Описание слайда:

Some String Methods indexOf(String subString) substring(int posBeg, int posEnd) toUpperCase(), toLowerCase() trim() replace(CharSequence targ, CharSequence replace) split(String regex) valueOf(value) – static

Слайд 10

Описание слайда:

indexOf method String palindrome = "Niagara. O roar again!"; System.out.println(palindrome.indexOf("roar")); What will be the output?

Слайд 11

Описание слайда:

substring Method String palindrome = "Niagara. O roar again!"; System.out.println(palindrome.substring(11, 15)); System.out.println(palindrome.substring(11)); What will be the output?

Слайд 12

Описание слайда:

replace Method String s = "Niagara. O roar again!"; s = s.replace("a", "A"); System.out.println(s); What will be the output?

Слайд 13

Описание слайда:

split Method String palindrome = "Niagara. O roar again!"; String[] txt = palindrome.split("r"); for (String t : txt){ System.out.println(t); } What will be the output?

Слайд 14

Описание слайда:

String Methods See for details

Слайд 15

Описание слайда:

Exercise 3.1.1. Write a program that computes your initials from your full name and displays them

Слайд 16

Описание слайда:

Exercise 3.1.1. See 311Initials project for the full text.

Слайд 17

Описание слайда:

Strings and Arrays It is impossible to work with strings as with arrays: String s="hello"; System.out.println(s[2]); // compile error From string to char array: char[] sArray = s.toCharArray(); From char array to string: String helloString = new String(sArray);

Слайд 18

Описание слайда:

String Formatting String s1 = ""; s1 = String.format("a =%1$3d, b =%2$7.2f, b = %2$6.4e", 12, 122.589); Output: a = 12, b = 122,59, b = 1.2259e+02 s1 = String.format("a =%1$3d, a =%1$4o, a = %1$2x", 43); Output: a = 43, a = 53, a = 2b See for details

Слайд 19

Описание слайда:

Format String The format string consists of static text embedded with format specifiers Except for the format specifiers, the format string is output unchanged Format specifiers begin with a % and end with a 1- or 2-character conversion that specifies the kind of formatted output being generated

Слайд 20

Описание слайда:

Format Specifiers d formats an integer value as a decimal value. f formats a floating point value as a decimal value. n outputs a platform-specific line terminator s formats any value as a string x formats an integer as a hexadecimal value tD formats date

Слайд 21

Описание слайда:

Examples of Format Specifiers System.out.format("%1f, %1$+012.10f %n", Math.PI); Output is 3.141593, +03.1415926536 System.out.format("%1$5s %2$7.5f", "e = ", Math.E); Output is e = 2.71828 See for detailes

Слайд 22

Описание слайда:

Application main Method Every application must contain a main method whose signature is: public static void main(String[] args) The main method accepts a single argument: an array of elements of type String This array is the mechanism through which the runtime system passes information to your application: java MyApp arg1 arg2

Слайд 23

Описание слайда:

How to Run Application with Arguments in Eclipse Right click on project name in the Package Explorer and select Run As > Run Configuration Go to Arguments tab and write argument values in the Program arguments field Press Apply button, then Run button

Слайд 24

Описание слайда:

Exercise 3.1.2. Create a program that will print every other argument given on the command line. If the program was executed with the following on the command line, java ArgumentSkipper one two three a b c d the program would print one three b d Consider how your program would operate when no arguments are given

Слайд 25

Описание слайда:

Run Application java app/E312Arguments one two three a b c d

Слайд 26

Описание слайда:

JAR Files The Java Archive (JAR) file format enables you to bundle multiple files into a single archive file Run JAR-packaged applications with the Java interpreter: java -jar jar-file

Слайд 27

Описание слайда:

Create JAR File in Eclipse Open workspace with necessary project Menu item File / Export Choose Java / Runnable JAR file in “Select an export destination”, then Next Select your project in “Launch configuration” dropdown list Fill “Export destination” field with JAR file name (Browse button can be used) Click Finish button

Слайд 28

Описание слайда:

Run Application java -jar ArgumentSkipper.jar one two three a b c d

Слайд 29

Описание слайда:

String vs StringBuilder Objects of the String class are immutable. A new String object is created during string modification. StringBuilder objects can be modified. StringBuilder objects are more effective when a lot of string modifications are needed

Слайд 30

Описание слайда:

StringBuilder Methods (1 of 2) indexOf(String subString) substring(int posBeg, int posEnd) length() The following are absent: trim() split(String regex) valueOf(value) – static

Слайд 31

Описание слайда:

StringBuilder Methods (2 of 2) append(type arg) - appends the argument to the string insert(int offset, type arg) - inserts the second argument into the string from offset replace(int start, int end, String s) - replaces the specified characters in this string reverse() - reverses the sequence of characters in this string See for details

Слайд 32

Описание слайда:

append Method StringBuilder s1 = new StringBuilder("Hello"); s1.append(" world!"); System.out.println(s1); What will be the output?

Слайд 33

Описание слайда:

insert Method StringBuilder s1 = new StringBuilder("Niagara again!"); s1.insert(7, ". O roar"); System.out.println(s1); What will be the output?

Слайд 34

Описание слайда:

replace Method StringBuilder s1 = new StringBuilder("Niagara. O roar again!"); s1.replace(7, 16, " "); System.out.println(s1); What will be the output?

Слайд 35

Описание слайда:

reverse Method StringBuilder s1 = new StringBuilder("Niagara. O roar again!"); s1.reverse(); System.out.println(s1); What will be the output?

Слайд 36

Описание слайда:

Exercise 3.1.3. A palindrome is a text phrase that spells the same thing backward and forward. The word redivider is a palindrome, since the word would spell the same even if the character sequence were reversed. Write a program that takes a word as an argument and reports whether the word is a palindrome

Слайд 37

Описание слайда:

Home Exercise 3.1.4. Create a generateString method that gets an integer argument n and returns a string contains first n integer numbers with gaps between them Create a generateStringBuilder method that does the same with StringBuilder class Compare these methods performance (with help of System.nanoTime();)