const nmax=20;
var a:array[1..nmax,1..nmax] of integer;
m,n,i,j,imx:byte;
x:integer;
begin
clrscr;
randomize;
repeat
write('Количество строк до ',nmax,' n=');
readln(n);
until n in [1..nmax];
repeat
write('Количество столбцов до ',nmax,' m=');
readln(m);
until m in [1..nmax];
writeln('Исходная матрица:');
for i:=1 to n do
begin
for j:=1 to m do
begin
a[i,j]:=random(50);
write(a[i,j]:4);
end;
writeln;
end;
writeln;
for j:=1 to m do
begin
imx:=1;
for i:=1 to n do
if a[i,j]>a[imx,j] then imx:=i;
x:=a[1,j];
a[1,j]:=a[imx,j];
a[imx,j]:=x;
end;
writeln('Обмен первых и максимальных в столбцах:');
for i:=1 to n do
begin
for j:=1 to m do
write(a[i,j]:4);
writeln;
end;
readln
end.