它重复地走访过要排序的数列，一次比较两个元素，如果他们的顺序错误就把他们交换过来。走访数列的工作是重复地进行直到没有再需要交换，也就是说该数列已经排序完成。(It repeatedly visits the sequence of items to be sorted, compares two elements at a time, and switches them over if their order is wrong. The work of visiting the sequence is repeated until there is no need to swap, which means that the sequence has been sorted.)