Let Us C++ Solution

 

                                   Getting Started

 

[A]  Which of the following are invalid variable names and why?

   BASICSALARY          (valid)

   _basic                           (valid)

   basic-hra                       (invalid , we cannot use hyphen in variable name)

  #MEAN                        (invalid , variable name must begin with an alphabet or underscore)

  group                             (invalid A  is not allowed in variable name)

  422                                 (invalid A variable name cannot begin with a digit)

  population in 2012         (invalid variable name cannot contain spaces)

  over time                        (invalid variable name cannot contain spaces)

 mindovermatter             (valid)

 FLOAT                           (valid)

 Hello                              (valid)

 queue                            (invalid A is not allowed in variable name)

 team'svictory               (invalid A ',, is not allowed in variable name)

 Plot # 3                        (invalid, The '#' and spaces are not allowed in variable name)

 2012_DDay                (invalid, A variable name must with an alphabet or an underscore)

             

[B]  Point out the errors, if any, in the following C statements:

(a) int = 314.562*150;

          Error. int is a keyword hence should not be used as a variable.

(b) name = 'Ali'

          Error. 'Ali' is an invalid character constant.

(c) varchar = '3'

          No error

(d) 3.14*r*r*h = vol_of_cyl;

          Error. on the left-hand side of equal to (=) there can only be a variable.

(e) k = (a * b) ( c + (2.5a + b) (d + e) ;

          Error. Multiplication operator (*) missing among the three expressions and also between 2.5 and variable a.

(f) m_inst = rate of interest * amount in rs;

          Error. rate of interest and amount in rs are invalid variable names.

(g) si = principal * rateofinterest * numberofyear / 100;

          No error.

(h) area = 3.14 * r ** 2;

          Error. '**' is an invalid operator.

(i) volume = 3.14 * r ∧ 2 * h;

         Error. The expression 3.14 * r will result in a float. the '∧ ' operator cannot be used with floats.

(j) k = ((a * b) + c) ( 2.5 * a + b);

         Error. Multiplication operator ( * ) missing between the two expressions given in parentheses.

(k) a = b = 3 = 4;

         Error. A constant 3 cannot be on the left hand side of the assignment operator.

(l) count = count + 1;

         No error.

(m) date = '2 Mar 04;

         Error. Double quotes ("") should be used instead of ('') to enclose the string 2 Mar 04.

[C] Evaluate the following expressions and show their hierarchy.

 

(a) g= big / 2 + big * 4 / big - big + abc / 3;

     (abc = 2.5, big = 2, assume g to be a float)

        Answer

          g  = 2 / 2 + 2 * 4 / 2 - 2 + 2.5 / 3          operation: /

          g = 1 + 2 * 4 / 2 - 2 + 2.5 / 3                operation: *

          g = 1 + 8 / 2 - 2 + 2.5 / 3                      operation: /

          g = 1 + 4 - 2 + 2.5 / 3                           operation: /

          g = 1 + 4 - 2 + 0.83                              operation: +

          g = 5 - 2 + 0.83                                    operation: -

          g = 3 + 0.83                                         operation: +

          g = 3.83

(b) on = ink * act / 2 + 3 / 2 * act + 2 + tig ;

       (ink = 4, act = 1, tig = 3.2, assume on to be an int)

         Answer

         on =  4 * 1 / 2 + 3 / 2 * 1 + 2 + 3.2        operation: *

         on =  4 / 2 + 3 / 2 * 1 + 2 + 3.2              operation: /

         on = 2 + 3 / 2 * 1 + 2 + 3.2                    operation: /

         on = 2 + 1 * 1 + 2 + 3.2                         operation: *

         on = 2 + 1 + 2 + 3.2                               operation: +

         on = 3 + 2 + 3.2                                     operation: +

         on = 5 + 3.2                                           operation: +

           on = 8