实现一个简单的菜单程序，运行时显示“Menu：A(dd) M(inus) Mu(ltify) D(ivid) Q(uit), select one”提示用户输入。A代表加法，M代表减法，Mu代表乘法，D代表除法，当用户输入其中之一时，产生两个随机数，并实现相应的算术运算。如此循环，直到输入Q，程序结束。-A simple menu program, run-time "Menu: A (dd) M (inus) Mu (ltify) D (ivid) Q (uit), select one" prompts the user. A representative of the addition of M on behalf of subtraction, Mu represents multiplication, D stands for division, when the user to enter one of two random number and the corresponding arithmetic operations. So the cycle until the Q-input, the end of the process.