Surprise Language Round 5 D. Date Change

• Time : $O(1)$
• Space : $O(1)$

Program-ID.D.
Data Division.
Working-Storage Section.
01    s    Pic    X(12).
01    t    Pic    X(12).
01    a    Pic    S9(12).
Procedure    Division.
Accept s.
string s(7:4) s(4:2) s(1:2) into t.
Accept s.
Move s to a.
Compute a=a+function Integer-of-Date(t).
Move function Date-of-Integer(a) to s.
Display s(7:2) "." s(5:2) "." s(1:4).
Stop run.