Why does my code result in unlimited ans = 1, when that is not in my code?

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Jake Burger 2014-3-18

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评论： dpb 2014-3-18

I am trying to get the result of righton, lefton, and input, but when I run the code it creates unlimited ans = 1. When I stop the code with ctrl+c I end up getting the answer I want. Why does "Ans = 1" show up when there is no "Ans" in my code? Here is a picture of my code. my code. Thanks in advance for your help!

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per isakson 2014-3-18

编辑：per isakson 2014-3-18

Your question is too hard for me to read, please markup!

The reason for ans = 1 is often that a function call without an ending ";" returns a logical true/false. ans is a special creature, which is created automatically.

Jake Burger 2014-3-18

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Yes it was the

else (right&left&center) < thresh

Thank you!

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Answer 1

dpb 2014-3-18

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编辑：dpb 2014-3-18

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The else clause is improperly formed--it cannot have anything as a conditional whereas you've written

else (right & left & center) < thresh

What you're seeing is as if the code were

else 
 (right & left & center) < thresh

The ans is the result of that comparison.

I haven't read the logic; if you need that actual comparison then need another elseif for it; if it's intended as indicating what the meaning of the else actually is then comment it out like

else % (right & left & center) < thresh

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Jake Burger 2014-3-18

I see now! Thank you, I tried your last option, as it turns out that statement is not needed since it is the only other option besides the two other elseif statements. Thanks again!

dpb 2014-3-18

I was little surprised Matlab didn't flag a syntax error--I'd've thunk it would have needed a endline character after the else. But, maybe that's just because I've written one-line if (test),action;end clauses for simple cases with the comma for so long out of habit I just never noticed that the comma might be omitted.

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