/*　　本程序实现的功能： 　　显示系统时间和日期 　　 该程序主要操作是： 　　使用了dos的系统调用功能，输入大小写D显示系统当前日期，当输入大小写T输出当前系统时间，当输入大小写Q退出程序，当输入其他字符时，提示错误 。 　　主要算法：将系统时间及日期转化成字符显示，通过堆栈来排序显示，同时涉及到 坐标位置设置的转换。时间和日期的显示都只调用了一个(函数)compute,避免了代码的冗余，尽量做到简洁，同时当一次操作过后，程序处于等待状态，以进行下一次操作，而非自动退出。该程序显示时间时多次调用显示功能，以达到动态效果。*/-/* This program features : The display system time and date of the program is the main operation : the use of the system call dos function, importation case-D display the current date, case-insensitive T when the input output current system, when the input Q withdraw from the case-sensitive procedure, when losers in other characters, suggesting error. The main algorithm : the system date and time into the characters, sorting through the stack to show that involves strategically placed to coordinate conversion. The time and date shown only a call (functions) compute avoid code redundancy, make it simple as possible, and at the same time after the operation, the procedure waits for the next operation, rather than retire. The program showed multiple calls time display, in order to achieve dy