作业题目是：将字符串"apple", "grape", "pear" 写入到磁盘文件f12-5.txt中，然后再从该文件中读出，显示到屏幕。-Job title is: the string " apple" , " grape" , " pear"　is written to a disk file f12-5.txt in, and then read from the file is displayed to the screen.