=                       Assignment Operator

 lvalue = exp            Assignment
 lvalue                  any variable
 exp                     any expression whose type is compatible with lvalue

    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) ...".