Can´t undertand 10th line instruction after inner FOR loop

Question

I've been studying "Algorithms and Data Structures" by N.Wirth. He codes his algorithms in a language he created: Oberon. I finished the book but I have one doubt about this algorithim of page 19 coded in Oberon:

PROCEDURE Power (VAR W: Texts.Writer; N: INTEGER);
    VAR i, k, r: INTEGER;
    d: ARRAY N OF INTEGER;
    BEGIN
        FOR k := 0 TO N-1 DO
            Texts.Write(W, "."); r := 0;
            FOR i := 0 TO k-1 DO
                r := 10*r + d[i]; d[i] := r DIV 2; r := r MOD 2;
                Texts.Write(W, CHR(d[i] + ORD("0")))
            END;
            d[k] := 5; Texts.Write(W, "5"); Texts.WriteLn(W)
        END
    END Power

The resulting output text for N = 10 is
.5
.25
.125
.0625
.03125
.015625
.0078125
.00390625
.001953125
.0009765625

I don´t understand what the instructions in line 10 d[k] := 5; Texts.Write(W, "5"); Texts.WriteLn(W) does:

1) Why you would you d[k] := 5? the program already printed all the output required (d[0] to d[k-1]).

2) why would you print a 5 after that? (Texts.Write(W, "5"))

Answer 1

The computation utilizes the fact that the last digit will always be five.

1. Unless the execution has finished, the variable d[k] is read in the next turn of the outer loop when r becomes 10*r + d[i] in the last turn of the inner loop
2. The statement Texts.Write(W, "5") requires (marginally) less computation than Texts.Write(W, d[i]).