[Bij]=[Aij],при j>=1
[Bij]=[Aji],при j<1
[Cij]=[Aij],при j<1
[Cij]=[Aji],при j>=1
uses crt;
const nmax=20;
var a,b,c:array[1..nmax,1..nmax] of integer;
n,i,j:byte;
begin
clrscr;
{randomize;}
repeat
write('Размер матрицы=');
readln(n);
until n in [1..nmax];
writeln('Исходная матрица:');
for i:=1 to n do
begin
for j:=1 to n do
begin
a[i,j]:={random(10)-4}10*i+j;{для наглядности, можно и рандомом}
write(a[i,j]:4);
end;
writeln;
end;
writeln;
writeln('Матрица В:');
for i:=1 to n do
begin
for j:=1 to n do
begin
if j>=i then b[i,j]:=a[i,j]
else b[i,j]:=a[j,i];
write(b[i,j]:4);
end;
writeln;
end;
writeln;
writeln('Матрица C:');
for i:=1 to n do
begin
for j:=1 to n do
begin
if j>=i then b[i,j]:=a[j,i]
else b[i,j]:=a[i,j];
write(b[i,j]:4);
end;
writeln;
end;
readln
end.