(* Pascal has what is known as reserved words - i.e. words that can not be used as 
   identifiers *)

(* the file extension you should use on your Pascal program files is .pp *)

(* your program header statement must contain the default device names if you are *)
(* reading from the keyboard OR writing to the screen *)
(* Pascal program header statements begin with the reserved word PROGRAM *)

PROGRAM identifier (input, output);

   VAR x, y, z : real;  (* variable declaration *)
       i       : integer;  
BEGIN

    (* := is the assignment operator in Pascal  *)
    (*   a semi-colon is a statement separator in Pascal   *)

       x := 3.5;

                         (*  input statements are in one of three forms *)
       read (x);         (* which gets a value from the default input device *)
       read (input, x);  (* which gets a value from the default input device *) 
       readln (x);       (* which gets a value from the default input device and then *)
                         (*   goes to the next "line of input" *)
       read( x,y,z);     (* which will get 3 values from the input device *)

     (* output statement come in one of three forms *)
        write (x);
        write (output, x:6:2);  (* the :6:2  formats the output away from exponential *)
                                (*   notation  *)
        writeln (x);  

     (* Pascal is NOT case sensitive *)
  
     (* counted loop and a PRE-TEST loop *)
     FOR i := 1 TO 10 DO   (* NEVER, EVER, put a semi-colon after a DO *)
        writeln (i);

     FOR i := 5 DOWNTO -1 DO
       BEGIN
         write ('hi  there ! ');
         writeln (i);  
     END;

      (*  another PRE-TEST loop - you have to modify the loop control variable manually *)
      (*  your loop should have at least 2 statements:  something you want done AND the *)
      (*  loop control variable modification  *)
      
     WHILE  i < 5 DO
       BEGIN
         writeln (' hello fellow ');
         i := i + 3;
       END;

                           (* the REPEAT UNTIL loop is a POST-TEST loop  *)
     REPEAT 
        writeln (' class will be over soon ');
        i := i - 2;
     UNTIL  i <  -3 ;
 
     IF i < 4 THEN
       writeln (' i is less than 4 ');

     IF  x > 0.3  THEN
       writeln (' x is greater than 0.3 ')  
     ELSE
       writeln (' x is less than 0.3  ');


     (* pascal has two types of sub-programs :  PROCEDURE and a FUNCTIOn  *)
     (* Pascal has two parameter passing modes:  VAR  and value  *)
     (* VAR parameters are passed by address  and the word VAR has to be there  *)
     (* value parameters are passed by being copied and are the default  *)


     

END.  (* the period following the END at the end of the program is required *)