12.7.. Napisati program koji će za učitanu vrijednost N izračunati vrijednost izraza i ispisati::

Opis rješenja:

Listing programa:

PROGRAM p12710036;
USES
 WinCRT;
VAR
  i, n, k: Integer;
  znak :-1..1;
  s, p: Real;
BEGIN
  Write('n=');
  Readln(n);
  Write('k=');
  Readln(k);
  znak := 1;
  s := 0;
  p:=1;
  i := 1;
  WHILE i <= n DO
    BEGIN
      p := p * i;
      IF i mod 3 = 0 THEN 
        BEGIN
          s := s + znak * k * p;
          znak := -znak;
        END;
      i := i + 1;
    END;
  Writeln('s=',s:4:0);
END.

II Varijanta
PROGRAM p12710036_2;
USES
 WinCRT;
VAR
  i,n, k: Integer;
  s, p, s1, s2 , p1: Real;
BEGIN
  Write('n=');
  Readln(n);
  Write('k=');
  Readln(k);
  s := 0;
  s1:=0;
  s2:=0;
  p:=1;
  i := 1;
  WHILE i <= n DO
    BEGIN
      p := p * i;
      IF i mod 6 = 0 THEN 
        s1 := s1 + p * k;
      IF i mod 6 = 3 THEN 
        s2 := s2 + p * k;
      i := i + 1;
    END;
  s := s2 - s1;
  Writeln('s=',s:4:2);
END.

Ispis na ekranu:

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