Variable in C++
A variable is an identifier that refers to the data item stored at a particular memory location.The value of a variable can be changed by assigning different values to is at various place in a progarm.
Declaration of variable
Declaration of variable allocates sufficient memory for variable. however, it does not store any data in the variables. To store data in variables, they need to be initialised at the time of declaration.
A Character set can be defined as a set of characters that either individually or in combination, represent information.In C++ a character set include the upper case(A-Z) lowe case (a-z) letters, decimal decimal digits(0-9), blank space(tabs,new line space,etc.) and special chatacter.
A token is defined as the smallest unit of program. When a program is compiled, the compiler scans the source code and parses it into tokens to find the the syntax errors. C++ token are broadly classified into keywords,identifiers,constants,operators & punctuators.