Why is my function giving me the wrong output?

Question

Kristen O'Mara 2018-2-21

0
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https://ww2.mathworks.cn/matlabcentral/answers/384019-why-is-my-function-giving-me-the-wrong-output

评论： Stephen23 2018-2-21

I was asked to write a function finding median and mean of an array without using the built in functions or the sum function. I think my code is very close to being correct, however I am confused as to why it is giving me the output zero when it should be giving me a 3. The array I tested it with was [5 8 9 1 0 2 3 1 9]. I then tried to sort it in ascending order and index it to find the median value. When I hover the cursor over the line

medianValue = sortedArray(medianIndex);

it shows the array as sorted. So basically, I don't know why my medianValue = 0 when it should equal 3. I think that part of my function is correct because it should be indexing the sorted array at the value for medianIndex, which is 5. So it should be returning the value 3.

   function [meanValue, medianValue] = statsFunction(array)
   %function to calculate median and mode values of an array
   sortedArray = sort(array, 'ascend');
   numElements = numel(sortedArray);
   if mod(numElements, 2) ~= 0
   medianIndex = (numElements+1)/2;
   medianValue = sortedArray(medianIndex);
   else
    medianIndex1 = numElements/2;
    medianIndex2 = (numElements+1)/2;
    medianValue = (medianIndex1 + medianIndex2) / numElements;
end
    sumx = 0;
    k = 1;
    while  k <= length(array)
    sumx = sumx + array(k);
    k = k+1;
 end
    meanValue = sumx/(length(array));