Vector. Change the way my program gives me the answer.

This program gives me the answer like this : c =

-3

c =

4

But I want the answer like this: c =

-3 4

The program:

v = [1 2 -3 4];
n = 1;
l = length (v);

while (n < l)
a = v(n);
b = v(n+1);
n = n+1;
if (a < 0 && b > 0)||(a > 0 && b < 0)
c = [b]
end
end

Answer 1

[Walter Roberson]

v = [1 2 -3 4];
n = 1;
l = length (v);

while (n < l)
a = v(n);
b = v(n+1);
if (a < 0 && b > 0)||(a > 0 && b < 0)
     c(n) = b;
else
    c(n) = nan;
end
n = n+1;
end

c

c = 1×3

NaN -3 4

[Julen Vicente Pipaon]

Thank you so much

Answer 2

[Paul Hoffrichter]

v = [1 2 -3 4];
n = 1;
l = length (v);
ii = 1;
c = [];
while (n < l)
   a = v(n);
   b = v(n+1);
   n = n+1;
%  if (a < 0 && b > 0)||(a > 0 && b < 0)
   if sign(a) ~= sign(b)
      c(ii) = [b];
      ii = ii + 1;
   end
end
disp(c);

[Julen Vicente Pipaon]

Thank you so much for your answer.

Answer 3

[Paul Hoffrichter]

v = [1 2 -3 4];
v( diff( sign( [v(1) v] ) ) ~= 0 )
ans =
    -3     4