EXPRESSION AND TYPE CASTING/CONVERSION

 Expression and Type Conversion : 

An expression is any valid combination of operators , constants and variables 

• Pure Expression : All the operands are of same types. 

• Mixed Expression : the Operands are of mixed expression or different data types. 

Type Conversion : the process of converting one predefined type into another is called TYPE CONVERSION.

•  Implicit type conversion : It is performed by the compiler without programmer's intervention. It convert all operands upto the type of the largest operands .

• Explicit type conversion : It is performed by the user is called Type Casting. It covert all the operands as per the given data types. 

Variables and constant: 

A variable is a named memory location , which hold data value of a particular data type. 

1. Global : Variables that are available inside any block of the program 

1. Local : Variables that are available inside the block in which they are created . 

1. Static : Variables that are called class variable share single memory between different objects. 

1. Instance : non static variables that share Different memory between different objects. 

1. Constant : If variable declared as Final than it is called as constant variable and Its value never changed in program. 

Precedence of operators : java has well defined rules for the operators in an expression Is evaluated. Precedence rules can be overridden by explicit parentheses . 

Associatively : Associatively is the grouping of operands and operators in an expression where more than one operator of the same precedence exist.