Variable Declaration, Constant, String Constant, Character Constant, Numeric Constant, Functions

Variable Declarations:-

                   Every variable needs to be declared before it is used in a program. Variable declaration provides following info the  compiler:-

·        How many bytes in the memory should be allowed for that variable.

·        What type of operation can be done on that variable.

·        What range of value can a variable consist.

A variable declaration consists of a data type followed by one or more variable names, ending with a semicolon. Syntax-

Datatype  var₁, var₂-------var_n;

Ex:- int a,b,c;

Constant:-

          Constant is a data intem that’s value can be changed during program execution. There are three types of constants-

•             String Constant
•            Character Constant
•            Numeric Constant

    String Constant:-

          A string constant is a sequence of alphanumeric characters enclosed in double quotation marks. The maximum length of a string constant is limited to 255 characters.

    Character Constant:-

          Character constant is either a single alphabet or single digit, or a single special symbol enclosed within a pair of single quotation mark.

    Numeric Constant:-

          Numeric constant has a constant value in numbers. The value of the constant can be positive or negative numeral. There are four type of numeric constants:-

·        Integer Constant

·        Floating Point constant

·        Octal Constant

·        Hex constant

Functions:-

          A function is a sub program that contains instructions or statements to perform some specific work.