var
a: array[1..4, 1..4] of integer;
i, j: integer;
sum: real;
begin
randomize;
writeln('исходная матрица');
for i := 1 to 4 do
begin
for j := 1 to 4 do
a[i, j] := random(10);
end;
for i := 1 to 4 do
begin
for j := 1 to 4 do
write(a[i, j], ' ');
writeln;
end;
for i := 1 to 4 do
begin
for j := 1 to 4 do
if i < j then begin
sum := sum + a[i, j];
end;
end;
writeln('сумма-----', sum);
writeln('элементы главной диагонали');
for i := 1 to 4 do
begin
for j := 1 to 4 do
if i = j then begin
write(a[i, j], ' ');
end;
end;
end.