=                        Assignment operator

 lvalue = exp            Assignment
 lvalue                  any variable
 exp                     any expression

    The assignment  operator '='  evaluates exp  and assigns  the resulting
    value to lvalue.

    The expression "lvalue = exp"  itself yields a value equivalent  to exp
    after  the  assignment  to  lvalue  is  made,  which  allows   multiple
    assignments such as 'a = b = 2'.

       Note:    A common error is to use = instead of == in a comparison
                test, such as "if ( a = b ) ...".