Selection sort also divides sequence in two parts. Sorted part and unsorted part.

Initially sorted kept doesn’t contain any element and the unsorted section contains the whole sequence. In every step the minimum element of the unsorted section is added to the sorted section by swapping the first element of unsorted section by the minimum element. Thus with every iteration, the size of the sorted sequence keeps on increasing. This process is continued until the length of sorted sequence becomes equal to the length of the sorted sequence.