1 4 3 2 1
2 0 0 0 4
3 0 0 0 3
4 0 0 0 2
1 2 3 4 1
uses crt;
const nmax=20;
var a:array[1..nmax,1..nmax] of integer;
n,i,j:byte;
begin
clrscr;
repeat
write('Размер матрицы до ',nmax,' n=');
readln(n);
until n in [1..nmax];
writeln('Исходная матрица:');
for i:=2 to n-1 do
for j:=2 to n-1 do
a[i,j]:=0;
for i:=1 to n-1 do
begin
a[i,1]:=i;
a[n,i]:=i;
a[1,n-i+1]:=i;
a[n-i+1,n]:=i;
end;
for i:=1 to n do
begin
for j:=1 to n do
write(a[i,j]:4);
writeln;
end;
readln
end.