const
n=4;
var
a:array[1..n,1..n] of integer;
i,j:integer;
b:boolean;
begin
for i:=1 to n do
begin
for j:=1 to n do
begin
a[i,j]:=random(2);
write(' ',a[i,j]:3);
end;
writeln();
end;
writeln('--------') ;
for i:=1 to n do begin
for j:=1 to n do
if ( (i=j) and (a[i, j]<>1) ) OR ( (i<>j) and (a[i, j]<>0) ) then begin
b := true;
break;
end;
if b then break;
end;
if b then write('матрица не является единичной');
writeln('--------') ;
end.