Entry Level Exam Question

What does the following code display?

V=[2 4 6 8];
for V = 1:2:5
if V>=3
disp('yes')
else
disp('no')
end
end
disp(V);

I know the output is:

no

yes

yes

5

But I'm not sure why. What determines the yes and no answers, and why does the value of V become 5? Any help?

[phillip kataswa]

The last number to iterate thorough the loop is 5. I think that instead of displaying the whole vector V

V is automatically changed to a scaler vector and only stores the last number that iterates through the loop.

Answer 1

[Walter Roberson]

Try this:

X = 999;
for X = 777; end
disp(X)

[Brian C]

So, is it completely rewriting the value of X?

[Walter Roberson]

Yes.

Answer 2

[Image Analyst]

The first V you made is essentially thrown away and never used.

V=[2 4 6 8]; % Never used at all.

When you do this:

for V = 1:2:5

you're saying that, in the loop, you want V to take on values 1, 3, and 5. It means (startvalue):(stepValue):(endingValue). After the loop, V retains its last value of 5 and that's what you print out.

[Brian C]

Got it, Thanks.