Why does my if statement do the opposite?

My if statement is asking that if h is negative, you must do that operation if not the other but do the opposite, do not I understand?

   t=b4
e=b3
f=b2
h=e^2-4*t*f
if h==-h
    qc=3
 p=(h)*(-1)
 x5=(sqrt(h))/(2*t);
 x6=(-e/(2*t));

 x7=(-sqrt(h))/(2*t);
 x8=(-h/(2*t));
else
    qd=4
x5=(-e+sqrt(h))/(2*t);
x6=(-e-sqrt(h))/(2*t); 
end

[Erwin Avendaño]

Answer 1

[David Goodmanson]

Hi Erwin

The test h==-h is not a test for whether h is negative. This test is the same as 2*h==0 and always fails unless h = 0. Take a look at h<0, or h<=0 if you intend the condition to work for h=0 as well as negative h.

[Erwin Avendaño]

haha you are right I had forgotten that for positives and negatives it was greater or less than ¡THX!

[Erwin Avendaño]

Is these two conditions okay? if (qb==2 && qd==4)

[David Goodmanson]

They are the right syntax anyway, assuming that qb and qd are scalars. I tend to just use & in every situation because it always works and I don't think it has slowed things down for what I ordinarily do.