Problem with sorting array algorithm

I have three arrays. And I am trying to sort all of them by one of them so. So my arrays are itemarray, pricearray, quantityarray. I want itemarray to be sorted but the corresponding arrays aren't sorting appropriately along with itemarray.

Here is the algorithm I created. Do you know how I can fix this??

DO i=1, NumItems-1

    SmallestItem = MINVAL(itemarray(i:NumItems))
    MINLOC_array = MINLOC(itemarray(i:NumItems))
    Locationsmallest = (i-1)+MINLOC_array(1)

    itemarray(Locationsmallest) = itemarray(i)
    itemarray(i) = SmallestItem

    pricearray(Locationsmallest) = pricearray(i)
    pricearray(i) = SmallestItem

    quantityarray开发者_开发知识库(Locationsmallest) = quantityarray(i)
    quantityarray(i) = SmallestItem

END DO  

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You are setting pricearray(i) to something that came from itemarray. You should be swapping pricearray(Locationsmallest) and pricearray(i), which you can do by storing the value of pricearray(Locationsmallest) in a temporary variable.

The same is true for quantityarray(i).

By the way, this is an O(n^2) algorithm, and is likely to be very slow when there are a large number of values in your array.