将ASC的码值在0到127之间的字符写到磁盘文件上，然后从文件中读出这些字符，判断读出的字符是否问可打印字符，若是则在屏幕上直接显示，否则将这些字符的十进制ASC码值输出到屏幕上。-The ASC code value from 0 to 127 characters written to a disk file, and then read from the file these characters to determine whether the character readout ask