Introduction to the Pascal Programming Language

© 1998 by Dr. Thomas W. MacFarland -- All Rights Reserved


     Instructions:   Review the following program and see if you can 
                     predict the outcome by completing a "pencil 
                     trace" of the code.  

                     Program output is provided at the end of this 
                     page.

     Compiler:       The program was prepared using Standard Pascal 
                     on a UNIX-based host computer.


% cat PASCAL/intro_pencil-03.p
{ Introduction to the Pascal Programming Language
  Dr. Thomas W. MacFarland
  intro_pencil-03.p       
}

{ The purpose of this program is to:

  1.  Demonstrate mathematical operations using integer variables.

  2.  Demonstrate mathematical operations using real variables.

  3.  Demonstrate the use of ( and ) for control of the order of 
      mathematical operation.  
}

program Demonstrate_Math_1;

var A, B : integer;
    C, D : real;

begin

   A := 19;
   B := (A + (A * 3)) * (A - (6 + 893));
   C := 19.98;
   D := ((C * C) - B) / (C + (A + 2.32));

   write('  A = ', A:8);
   write('  B = ', B:8);
   write('  C = ', C:8:3);
   write('  D = ', D:8:3); writeln;

end.  { intro_pencil-03.p      } 
% pc PASCAL/intro_pencil-03.p
% a.out
  A =       19  B =   -66880  C =   19.980  D = 1629.036

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