ITFT-Constants, variables and data types in java

ITFT-Constants, variables and data types in java

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  CONSTANTS, VARIABLES AND DATATYPES
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  Introduction • A programminglanguage is designed to process certain kind of data consisting of numbers, characters and string and to provide useful output called information • The task of processing data is accomplished by executing a sequence of instruction known as program. • The instructions are formed using certain symbols and words according to some rigid rules known as syntax rule or grammar. • Like any other language java also have its own vocabulary and grammar. Know we will discuss concepts of constants and variable and their data type.
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  Constants
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  Integer constant An integerconstant refers to a sequence of digits. There are three types of integers, namely, decimal integer, octal integer and hexadecimal integer • Decimal integer: - consist of a set of digit through 0 to 9, which may be proceeded by optional sign minus e.g. 7897,-64864, and 0 etc. • Octal integer: - consist of a set of digit through 0 to 7, with preceding 0. For example: - 037, 0 0465, etc. • Hexadecimal integer: - consist of a set of digit through 0 to 9 and A through F or a through f, with preceding 0x or 0X. For example: - 0x37, 0x, 0X465AF, 0xfcb23, etc.
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  Real Constants The quantitieswhich are represented by numbers containing fraction parts are known as Real or Floating point constant. For example 0.0086, -0.75 etc • A real number can also be represented in scientific notation like 2.15e2 here e2 means 102. • The general syntax is Mantissa e exponent
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  Character Constants A singlecharacter constant contains a single character enclosed with in a pair of single quote mark. Example: - ‘a’,’A’,’12’
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  String constant A stringconstant is a sequence of character enclosed between double quote. Example: “hello”, ”java”
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  Backslash character constant JavaAlso Supports Backslash Constants those are used in output methods For Example n is used for new line Character. These are also called as escape Sequence or backslash character Constants. Backslash Code Description t tab character n new line or line feed character r carriage-return character f form-feed character a alert or bell character e escape character cx control character corresponding to x backslash character 0n character with octal value 0nn character with octal value 0mnn character with octal value xhh character with hexadecimal value uhhhh character with hexadecimal value
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  Data Types
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  INTEGER TYPES • Aninteger is a whole number — that is, a number with no fractional or decimal portion. Java has four integer types, which you can use to store numbers of varying sizes. Type Number of Bytes Range of Values byte 1 –128 to +127 short 2 –32,768 to +32,767 int 4 –2 billion to +2 billion long 8 -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
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  Floating point types •Floating-point numbers are numbers that have fractional parts (usually expressed with a decimal point). You use a floating-point type in Java programs whenever you need a number with a decimal, such as 19.95 or 3.1415. • Java has two primitive types for floating- point numbers: • float: Uses 4 bytes • double: Uses 8 bytes • In almost all cases, you should use the double type whenever you need numbers with fractional values.
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  Character type • chardata type is a single 16-bit Unicode character. • Minimum value is 'u0000' (or 0). • Maximum value is 'uffff' (or 65,535 inclusive). • Char data type is used to store any character. • Example . char letterA ='A'
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  Boolean Type • Booleandata type represents one bit of information. • There are only two possible values: true and false. • This data type is used for simple flags that track true/false conditions. • Default value is false. Example : boolean one = true