uses crt;
const nmax=20;
var a:array[1..nmax,1..nmax] of integer;
m,i,j:byte;
begin
clrscr;
randomize;
repeat
write('Размер матрицы=');
readln(m);
until m in [1..nmax];
writeln('Исходная матрица:');
for i:=1 to m do
begin
for j:=1 to m do
begin
a[i,j]:=random(10)+1;
write(a[i,j]:4);
end;
writeln;
end;
writeln;
for i:=1 to m do
for j:=m-i+1 to m do
a[i,j]:=0;
writeln('Измененная матрица:');
for i:=1 to m do
begin
for j:=1 to m do
write(a[i,j]:4);
writeln;
end;
readln
end.