uses crt;
const n=6;
var
a:array[1..20,1..20] of integer;
i,j,x:integer;
Begin
write('Матрица: ');
writeln;
randomize;
for i:=1 to n do
begin
for j:=1 to n do
begin
a[i,j]:=random(10)-5;
write(a[i,j]:3,' ');
end;
writeln;
end;
for i:=1 to n do
begin
x:=a[i,3];
a[i,3]:=a[i,i];
a[i,i]:=x;
end;
writeln;
writeln('После обмена: ');
writeln;
for i:=1 to n do
begin
for j:=1 to n do
begin
write(a[i,j]:3,' ');
end;
writeln;
end;
end.