use a stack to reverse the words of a sentence. keep reading words until you have a word that ends in a period, adding them onto a stack. when you have a word with a period, pop the words off and print them. stop when there are no more words in the input. for example, you should turn the input mary had a little lamb. its fleece was white as snow. into lamb little a had mary. snow as white was fleece its. pay attention to capitalization and the placement of the period.