NCERT Computer: Chapter 7 – Introduction to C + + Part 3
A token is a group of characters that logically belong together. The programmer can write a program by using tokens.
C++ uses the following types of tokens.
There are some reserved words in C++ which have predefined meaning to complier called keywords.
Some commonly used keywords are given below:
Symbolic names can be used in C++ for various data items used by a programmer in his program. For example, if a programmer wants to store a value 50 in a memory location, he/she choose any symbolic name (say MARKS) and use it as given below:
MARKS = 50
The symbol ‘=’ is an assignment operator.
The significance of the above statement is that ‘MARKS’ is a symbolic name for a memory location where the value 50 is being stored.
A symbolic name is generally known as an identifier. The identifier is a sequence of characters taken from C++ character set.
The rules for the formation of an identifier are:
An identifier can consist of alphabets, digits and/or underscores.
It must not start with a digit.
C++ is case sensitive, i.e., upper case and lower case letters are considered different form each other. It may be noted that TOTAL and total are two different identifier names.
It should not be a reserved word.