data-types

 Data type

Integer types

•  Integer types can hold whole number such as 123, -97 and 6543.

• The size of the values that can be stored depends on the integer data type we choose.

•  Java defines four integer types: byte, short, int and long. All of these are signed it means positive or negative values. Java does not support unsigned types.

•  It should be remember that wider data types require more time for manipulation and therefore it is advisable to use smaller data types, wherever possible.
• For example, instead of storing number like 56 in an int type variable, we have to use a byte type variable to handle this number. This will improve the speed of execution of the program.

Floating point types

•  Integer types can hold only whole numbers and therefore we use another type known As Floating point type to hold numbers containing fractional part such as 22.43 and -2.346 .

• Floating-point numbers, also known as real numbers, are used when evaluating expressions that require fractional precision.

• There are two kinds of floating point storage float and double which represent single-and double-precision numbers, respectively.
• Double precision types are used when we need greater precision in storage of floating point numbers.
•  All mathematical functions such as sin,cos and sqrt return double type values.

Character type

•  In order to store character constants in memory, java provides a character data type called char.

• The char type assumes a size of 2 bytes but, it can hold only a single character.

Boolean type

• Boolean type is used when we want to test a particular condition during the execution of the program.

• There are only two values that a boolean type can take that is true or false.
•  Boolean type is denoted by the keyword boolean and uses only one bit of storage.
• All comparison operators return boolean type values.
• Boolean values are often used in selection and iteration statements.
•  The words true or false can not be used as identifiers.