在程序运行时,经常需要输入一些数据,数据输入的正确与否影响到程序的正常运行.因此,有必要对输入的数据进行检验.过滤掉不合法的数据.-in running, often need to import some data data input correct or not affect the normal operation procedures. Therefore, it is necessary to input data for examination. do not filter out