while loop with else if statement

I've attached a screenshot below, wondering why I can't get the loop to go through each if/elseif/else statement. I keep getting the first fprintf output under my first if statement no matter what value i get. What am i missing?

Answer 1

[Walter Roberson]

You have

if Gforce >= 7 || Gforce < 9

Consider the opposite for a moment:

if ~(Gforce >= 7 || Gforce < 9)

which is equivalent to

if Gforce < 7 && Gforce >= 9

Are there any finite numbers which are simultaneously less than 7 and greater than or equal to 9? NO! And if the opposite of a test selects for nothing, it follows that the original test selects for everything finite.

5 -> is less than 9, so succeeds

8 -> is greater than 7 and also less than 9, so succeeds

11 -> is greater than 7, so succeeds

The only scalar numeric value for Gforce that would not pass the >=7 || < 9 test, is if Gforce is NaN.

else Gforce > 11

Notice you did not use elseif there, so as far as MATLAB is concerned, that section of code is equivalent to

else
    Gforce > 11

with Gforce > 11 resulting in a logical computation whose result is displayed (because there is no semi-colon following it to tell it not to display), and whose value does not otherwise affect the outcome of the code.