Variables and Data types

          Create a program that will let the user input its name and password, if input name and password is correct end the program. If Name and password is wrong end the program.

•Variables in Java have a type.

•The type defines what kinds of values a variable is allowed to store.

•Integer Types:

–int: Most numbers you’ll deal with.

–long: Big integers; science, finance, computing.

–short: Small integers. Legacy. Not very useful.

–byte: Very small integers, useful for generic data.•Floating Point (Decimal) Types:

–float: Single-precision decimal numbers

–double: Double-precision decimal numbers.

•Other Types:

–String: Text strings.

–boolean: True or false.

–char: Latin Alphanumeric Characters

•Variable names (or identifiers) may be any length, but must start with:

–A letter (a – z),

–A dollar sign ($),

–Or, an underscore ( _ ).

•Identifiers cannot contain special operation symbols like +, -, *, /, &, %, ^, etc.

•Certain reserved keywords in the Java language are illegal.

•For example, “class”, “static”, “int”, etc.

•Java is a case-sensitive - capitalization matters.

•“Camel Case”: Start variable names with lower case and capitalize each word: “camelsHaveHumps”.

Data Type	Description
byte	Variables of this kind can have a value from: -128 to +127 and occupy 8 bits in memory
short	Variables of this kind can have a value from: -32768 to +32767 and occupy 16 bits in memory
int	Variables of this kind can have a value from: -2147483648 to +2147483647 and occupy 32 bits in memory
long	Variables of this kind can have a value from: -9223372036854775808 to +9223372036854775807 and occupy  64 bits in memory