pascalfreepascal

Why is the output 16 bits when I'm only telling it to write 15?

Hello everyone once again,

I need to write a code in Pascal which converts a decimal number into a binary number, and saves this into an array, and then writes it from MSD to LSD.

I've got most of the code, however when I want to print it, I don't understand one significant thing:

I put the codesnippet

FOR i := 15 DOWNTO 1 DO
write(Integer(dualCalc[i]));

as output. When I run this program, I get the number 0000000000001010 as output, which is correct and also 16 bits. How? 15 DOWNTO 1 is only 15 bits, so how is the output 16 bits?

When I put

FOR i := 15 DOWNTO 0 DO
write(Integer(dualCalc[i]));

I get 00000000000010100, which is just wrong and 17 bits.

Can someone explain to me how this is possible?

Entire Code below.

PROGRAM ConvertNum;


TYPE
dual = ARRAY[0..15] OF BOOLEAN;


PROCEDURE Dec2Dual (decimal: INTEGER; VAR dualCalc: dual); 

VAR


i: INTEGER;
calculation: INTEGER;
divisionBool: BOOLEAN;


BEGIN

i := 0;    


WHILE (i < 16) AND (decimal > 0) DO
    BEGIN
        calculation := decimal mod 2;
            IF calculation = 0 THEN
            divisionBool := FALSE
            ELSE
            divisionBool := TRUE;
        dualCalc[i] := divisionBool;
        decimal := decimal div 2;
        i := i + 1;
    END;


FOR i := 15 DOWNTO 0 DO
write(Integer(dualCalc[i]));


END;

VAR

aThree: ARRAY[0..15] OF BOOLEAN;
inputVar: INTEGER;
DecOut: INTEGER;

BEGIN

readln(inputVar);

Dec2Dual(inputVar, aThree);

END.
Solution