1. Заполнить магический квадрат (25,8,11,14,17,20,23,26), составить свой магический квадрат.

2. Придумать алгоритм-фокус.

3. Решить алгоритм Гаусса (4,5,6,7,8,9,10,11,12,13)

Магический квадрат с n сторон

const

mn = 16;

var

p: Boolean;

procedure Swap (var a, b: Integer) ;

var

T: Integer;

begin

T : = a; a : = b; b : = T

end;

procedure CreateMagic (n: Integer) ;

var

i, j, k, s, b, r, m: Integer;

a: Array[1 ... mn, 1 ... mn] Of Integer;

begin

p : = True;

if Odd (n) Then

begin

i : = 1; j : = Succ (n div 2) ;

for k : = 1 To Sqr (n) do

begin

a[i, j] : = k;

if k mod n = 0 Then Inc (i)

Else

begin

Dec (i) ; Inc (j) ;

if i = 0 Then i : = n;

if j > n Then j : = 1

end

end;

end

Else

if n mod 4 = 0 Then

begin

k : = 1;

for i : = 1 To n Do

for j : = 1 To n Do

begin

a[i, j] : = k; Inc (k)

end;

j : = 2; m : = n div 2;

for i : = 1 To m Do

for k : = 1 To m Div 2 Do

begin

if j = Succ (m) Then j : = 2

Else

if j = (m + 2) Then j : = 1;

s : = Succ (n - i) ; b : = Succ (n - j) ;

Swap (a[i, j], a[s, b]) ;

Swap (a[i, b], a[s, j]) ;

Inc (j, 2)

end

end

Else

if n 2 Then

begin

k : = 1;

for i : = 1 To n Do

for j : = 1 To n Do

begin

a[i, j] : = k; Inc (k)

end;

r : = Pred (n div 2) div 2; m : = n div 2;

for i : = 1 To m Do

begin

j : = i;

for k : = 1 To r Do

begin

if j > m Then j : = 1;

s : = Succ (n - i) ; b : = Succ (n - j) ;

Swap (a[i, j], a[s, b]) ;

Swap (a[i, b], a[s, j]) ;

Inc (j)

end

end;

i : = 1;

for k : = 1 To m Do

begin

if j > m Then j : = 1;

s : = Succ (n - i) ;

Swap (a[i, j], a[s, j]) ;

Inc (i) ; Inc (j)

end;

i : = 1; j : = r + 2;

for k : = 1 To m Do

begin

if j > m Then j : = 1;

b : = Succ (n - j) ;

Swap (a[i, j], a[i, b]) ;

Inc (i) ; Inc (j)

end

end

Else p : = False;

if p Then

begin

for i : = 1 To n Do

begin

for j : = 1 To n Do

Write (a[i, j]: 4) ;

WriteLn

end

end

Else

WriteLn ('do not exists')

end;

var

n: Integer;

begin

WriteLn ('n = ') ; ReadLn (n) ;

CreateMagic (n) ;

end.