本程序采用分类询问的模式，对要求的方法一一用函数实现，并在函数中根据客户的要求调用子函数。通过递归调用todo（）函数，不断实现用户想要实现的功能，最后以输入0，结束循环，程序结束。-The inquiry procedure uses classification model, the methods required to achieve one by one with the function and function call Functions according to customer requirements. Through the recursive call todo () function, users want to achieve and continuously realizing the function, the last to enter 0 to end the cycle, the program ends.