Variables-: a variable data name that may be used to store a data value only constant that remain unchanged during the execution of a program a variable may take different values at different times during execution we used several variable.variable store the value of money at the end of each year A variable name can be chosen by the programmer in a meaningful way so as to replace function or nature in the program some example of some names are here height, Total, weight, amount etc.
Variable name may consist of letter, digits and the underscore character(_) subject to the following conditions
1 they must begin with a letter some system permit underscore as the first character .
2.ANSI standard recognizes a length of 31 characters however length should not be normally more than 8 characters since only the first 8 characters are treated as significant by many compilers
3. uppercase and lowercase are significant that is the variable total is not the same as total equity TOTAL .
4. it should not be a keyword.
5 white space is not allowed some
Valid variable are here example are here Ram, Shyam, Mohan, Sohan Delhi Rajasthan