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Sarah K
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calculating percentage change function

Asked by Sarah K
on 22 Oct 2019
Latest activity Commented on by dpb
on 22 Oct 2019
Hi,
I am high school china. want to build a function for two input variables (two judges scores) and calculate the percentage difference between them.
function [outcome] = judges_scores(input1, input2)
pct_difference = 100*(input1-input2)./input2);
if (pc_difference = 0)
disp('pass');
else (pc_difference < 0) && (pc_difference > 0)
disp('fail');
end
I would like some assistance, especially how to calculate percentage difference for two inputs in a function. Thank you.

  1 Comment

dpb
on 22 Oct 2019
Your function calculates the percentage difference between the two judges' scores presuming the second is the reference. What you'll get as a numeric value will depend on which is the reference...if the reference is higher than the other, you'll get a value <0 of somewhat smaller absolute magnitude than vice versa:
>> J1=95;J2=92;
>> (J1/J2-1)*100
ans =
3.2609
>> (J2/J1-1)*100
ans =
-3.1579
>>
How to treat this is up to your problem definition which isn't given so we can't answer that part.
NOTA BENE:
You defined the percent difference as pct_difference, however you missed the t on pct in the |if...else...end clause so it's undefined.
You also called your function return value outcome but it is never defined in the function so don't have any return value.

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1 Answer

Answer by Rik
on 22 Oct 2019

You should use = for an assignment and == for a comparison. Another point is that you don't need a conditional for an else, only for an elseif.
Note that a comparison with 0 might lead to unexpected results in edge cases. Comparing the abs to eps should be more reliable (and would provide an easy way to modify your tolerance.

  1 Comment

Also note that ‘outcome’ is not assigned.

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