sort2.cc From Astrachan, p 531
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void Sort(Vector<int> & a, int numElts)
// precondition: a contains numElts ints
// postcondition: elements of a are sorted in non-decreasing order
{
    int j,k,temp,minIndex;

    for(k=0; k < numElts - 1; k++)
    {
        minIndex = k;                 // smallest item from k to end of a
        for(j=k+1; j < numElts; j++)
        {
            if (a[j] < a[minIndex])
            {
                minIndex = j;         // new smallest item, remember where
            }
        }
        temp = a[k];                  // swap smallest item and k-th item
        a[k] = a[minIndex];
        a[minIndex] = temp;
    }
}