在键盘上接收用户输入的15个整数数值，输入完成后，接收用户输入的指令，如果用户输入a(大小写不区分)升序排列，如果输入d(大小写不区分)降序排列，否则提示用户重新输入指令,输出排序前与排序后的数列内容。(, on the keyboard to receive 15 integer value of user input, the input is completed, receiving the command input by the user, if the user input a (not case distinction) in ascending order, if the input D (not case distinction) in descending order, or prompt the user to input, output and content of the sorted sequence before ordering the.)