There are several ways to do this. One way is to make a counter, and increment that counter each time through the loop:
p=[1:1:20]';
k = 0; % <-start a counter
for x=.1:.1:1
k=k+1; % <-increment the counter
q(:,k)=x.*p; % <- log the result
end
Another way is very similar, but some would say better coding style:
p=[1:1:20]';
x=.1:.1:1;
for k = 1:length(x)
q(:,k) = x(k).*p;
end
Or of course if all you need is the cross product you can skip the loops altogether:
p=[1:1:20]';
x=.1:.1:1;
q = p*x;
