Data Types, Variables and Arrays

 Java defines 8 primitive(simle) types of data: byte, short, int, long, char, float, double, boolean. 

Byte - the smallest integer type. This is a signed 8-bit type that has a range from -128 to 127.

Short - is a signed 16-bit type. It has range from -32,768 to 32767.

Int - is a signed 32-bit type that has a range from -2,147,483,648 to 2,147,483,647. 

Long - is a signed 64-bit type.

Float - specifies single-precision value that uses 32 bits of storage.

Double - uses 64 bits of storage.

Char - is 16-bit type. The range of a char 0 to 65,536. There are no negative chars.

Boolean - has two possible values true or false.

Integer Literals. An integer literal can always be assigned to a long variable. You do this by appending an

upper- or lowercase L to the literal. For example, 0x7fffffffL or 12345L. 

You can also specify integer literals using binary. To do so, prefix the value with 0b or 0B.  int x = 0b1010;

Octal values are denoted in Java by leading zero.Normal decimal numbers cannot have a leading zero.

Underscores can only be used to separate digits, and can not come at the beginning or the end of a literal.

Ex: int x = 123__555_1233;

Each time you start a new block, you are creating new scope. A variable declared within a block is called a local variable.Objects declared in the outer scope will be visible to code within the inner scope.

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Изображение
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