Mảng hai chiều_ xuất số hình xoắn ốc

program xoan_oc;
uses crt;
var a:array[1..50,1..50] of integer;
i,j,n,h,dem: integer;
begin
clrscr;
write(`nhap n: `); readln(n);
for h:=1 to trunc(n div 2) do
begin
for j:=h to n-h do
begin
inc(dem);
a[h,j]:=dem;
end;
for i:=h to n-h do
begin
inc(dem);
a[i,n-h+1]:=dem;
end;
for j:=n-h+1 downto h+1 do
begin
inc(dem);
a[n-h+1,j]:=dem;
end;
for i:=n-h+1 downto h+1 do
begin
inc(dem);
a[i,h]:=dem;
end;
end;
{neu n chan thi vong lap tren se chay het tat ca cac vi tri
con ma n le thi khong chay toi duoc vi tri trung tam cua mang nen phai ep vao}
if n mod 2<>0 then a[round(n/2),round(n/2)]:=n*n;
{in ra}

writeln(`ket qua:`);
for i:=1 to n do
begin
for j:=1 to n do write(a[i,j]:4);
writeln;
end;
readln;
end.