Selection sort works as follows.

• The array of values to be sorted is divided into two partitions: the partition of sorted values and that of unsorted values.
• In each step of selection sorting, the smallest element in the unsorted partition is picked up and is added to the end of the sorted partition.
• The sorting proceeds until the elements in the unsorted partition are exhausted.
• We use floorIdx to designate the last element in the sorted partition.
• The array elements with indexes 0 through floorIdx are in the partition of sorted values, and the rest in the patition of unsorted values.
• The first element of the unsorted partition has array index floorIdx + 1.
• Initially, no elements in the array belong to the sorted partition, and hence floorIdx = -1.
• While the smallest value in the unsorted partition is being slected, the smallest value found so far is kept in minValue.
• Sorted values are shown in purple, and unsorted values in green.