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-11.p
{ Introduction to the Pascal Programming Language
  Dr. Thomas W. MacFarland
  intro_pencil-11.p       
}

{ The purpose of this program is to:

  1.  Demonstrate integer math.

  2.  Demonstrate a for/do loop, a loop with a set number of 
      iterations.    

  3.  Demonstrate the use of ( and ) to direct the order of
      operations.
}

program Demonstrate_More_Activities_With_Integers;

var A, B, C, D:  integer;

begin

   writeln;
   for A := -2 to 3 do begin
     B := 10 + 5 * A;
     C := (10 + 5) * A;      
     D := 10 + ((A * 7) mod 2);
       
     write('  A = ', A :5); write('  B = ', B :5);
     write('  C = ', C :5); write('  D = ', D :5);

     if A >= 2 then
       write('  A >= 2') else write('  A < 2'); writeln;
   end;

end.  { intro_pencil-11.p      } 
% pc PASCAL/intro_pencil-11.p
% a.out

  A =    -2  B =     0  C =   -30  D =    10  A < 2
  A =    -1  B =     5  C =   -15  D =     9  A < 2
  A =     0  B =    10  C =     0  D =    10  A < 2
  A =     1  B =    15  C =    15  D =    11  A < 2
  A =     2  B =    20  C =    30  D =    10  A >= 2
  A =     3  B =    25  C =    45  D =    11  A >= 2

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