Lecture 2 - OutlineJava Program StructureCharacter StringsInteractive Program - OutputThe print MethodNote:Exercise:String ConcatenationSpecial Characters:Escape SequencesSlide 11OutlineVariablesVariablesPrimitive DataNumeric Primitive DataPrimitive Data - CharactersPrimitive Data - Character SetsPrimitive Data - CharactersSlide 20BooleanConstantsSlide 23Slide 24AssignmentExpressionsDivision and RemainderOperator PrecedenceOrder of OperationsSlide 30Slide 31Slide 32Slide 33Assignment RevisitedSlide 35Increment and DecrementPostfix and Prefix operatorsSlide 38Order of Operations:Assignment OperatorsSlide 41Examples:Slide 43Data ConversionSlide 45Slide 46PromotionAssignment ConversionCastingSlide 50Strings as ObjectsSlide 52Slide 53Strings MethodsString MethodsSlide 56Interactive Programs - InputReading InputInput TokensSlide 60In Class ChallengeLecture 2 - Outline2-1Character StringsVariablesPrimitive Data Types ConstantsAssignments and ExpressionsData ConversionThe String ClassInteractive ProgramsJava Program Structure1-2public class HelloWorld{}// Hello World Applicationpublic static void main (String[] args){}// Java application to display the message// Hello World on the screenSystem.out.println("Hello World!");Character StringsA string literal is a sequence of zero or more characters enclosed by double quotes.Examples:"Hello World!""This is a string literal.""123 Main Street""X"The empty string ("") is the string with no charactersString literals cannot extend over more than one line.2-3System.out.println( "Hello World!“);The Java compiler will report a syntax errorInteractive Program - Output•To display information on the console, Java uses methods of the object System.out•The System.out object represents the monitor screen to which we can send output.•The method println display a string to the screen, then move to the next line2-4System.out.println ("Go Dawgs!!!.");objectmethodnameinformation provided to the method(argument/parameter)The print Method•The print method is similar to the println method,But, it does not skip to the next line after displaying the string. It leaves the cursor where ever the last letter was printedExample:2-5System.out.print("Merry Christmas"); System.out.println("and Happy New Year.");Merry Christmasand Happy New Year.Note:•If you want to leave a space between the words “Christmas ” and “and” you must add it either after Christmas or before and. System.out.print (“Merry Christmas ”); System.out.print (“and happy new year”); 2-6Exercise:•What is the output of the following statements? System.out.print (“I am”); System.out.print(“a student”); System.out.println (“ of:”); System.out.println (“Java”);2-7I ama student of:JavaString ConcatenationThe string concatenation operator (+) is used to append one string to the end of anotherSystem.out.println ("cats " + "and dogs“);You can also be used to append a number to a string.System.out.println("UGA Sugar Bowl Champions "+ 2009);The + operator is the concatenation operator when one of the operands is a string.2-8Special Characters:•How can we display the following output ?Error. Why ?System.out.println (“He said “time is a great teacher”);2-9He Said “Time is a great teacher”Escape Sequences•Special characters are represented in a string using a escape sequence.•An escape sequence is a series of characters that represents a special character•An escape sequence begins with a backslash character (\).2-10Escape Sequence\b\t\n\r\"\'\\Meaningbackspacetabnewlinecarriage returndouble quotesingle quotebackslashSystem.out.println(“He said: \“ Time is a great teacher \“ “); System.out.println(“Harry Potter\nis very-very \n\nfamous “); 2-11He Said “Time is a great teacher”Harry Potter is very-veryFamousOutline2-12Character StringsVariables,Primitive Data Types and ConstantsAssignments and ExpressionsData ConversionThe String ClassInteractive ProgramsVariablesA variable is a name for a location of memory that stores a valueThe value of the variable may change during the execution of the programA variable must be declared by specifying the variable's name and the type of data that it will holdBy convention, variables names starts with a lowercase letter 2-13int total;int x, y, z;data typevariable nametotalxyzVariables•After declaring a variable inside a method (main method in our case) you can use it anywhere inside the body of that method.int total ;total = 50; // java is case sensitive.//therefore Total = 50; is a syntax error2-14•A variable can be given an initial value in the declarationint sum = 0;int base = 32, max = 149;sum0base32max149Primitive DataThere are eight primitive data types in JavaInteger data types:byte, short, int, long Floating point numbers data types :float, doubleCharacters:charBoolean:boolean2-15Numeric Primitive Data•The difference between the various numeric primitive types is their size, and therefore the range of values they can hold:2-16TypebyteshortintlongfloatdoubleStorage8 bits16 bits32 bits64 bits32 bits64 bitsMin Value-128-32,768-2,147,483,648< -9 x 1018+/- 3.4 x 1038 7 significant digits+/- 1.7 x 10308 15 significant digitsMax Value12732,7672,147,483,647> 9 x 1018TypebyteshortintlongfloatdoubleStorage8 bits16 bits32 bits64 bits32 bits64 bitsMin Value-128-32,768-2,147,483,648< -9 x 1018+/- 3.4 x 1038 7 significant digits+/- 1.7 x 10308 15 significant digitsMax Value12732,7672,147,483,647> 9 x 1018Primitive Data - Characters•A char variable stores a single character•Character literals are delimited by single quotes:'a' 'X' '7' '$' ',' '\n'•Example declarations:char topGrade = 'A';char terminator = ';', separator = ' ';•A character variable holds only one character. 2-17Primitive Data - Character SetsA character set is an ordered list of characters, with each character corresponding to a unique number or codeJava uses the Unicode character set It is an international character set, containing symbols and characters from many world languagesUses sixteen bits per character, allowing for 65,536 unique charactersA char variable in Java can store any character from the Unicode character set.2-18Primitive Data - Characters•The ASCII character set is older and smaller than Unicode, but is still quite popular•The ASCII character set is a subset of the Unicode character