Variables

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Variables

  • Definition of variables:
          A variable is a name of data that is used to store the value of data. In C programming language a variable is the named memory location where a program can manipulate the data. This location is used to hold the value of the variable. The value of the C variable may get a change in the program as it depends on the type of program. You can think of a variable as being equivalent to its assigned value.
             A variable name can be chosen by the programmer in a meaningful way so as to reflect its function or nature in the program.
  • Some examples of names are,
                     sum
                     average
                     total
                     counter_1
                     class 

  • Condition/rules for naming variable:-  
  1. A variable name must begin with a letter or underscore.
  2. Variable are case sensitive. The variable Total is not the same as TOTAL or total.
  3. ANSI standard recognizes a length of 31 characters.
  4. White space is not allowed.
  5. No, any special characters/symbols are allowed other than underscores.
  6. It should not be a keyword.
  • Some example of the valid variable names:
                  sum          sum3         div
                  delhi         sum_3       S_um
                  mark        T_rais        Name

  • Some example of the invalid variable name:
         Char    -      keyword is not valid
         sum$    -     special character is not valid
         1323     -     starting from number is not valid
         avg value - white space is not valid     



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