完成大数求幂的程序。要求按照运算符重载版本完成，类的声明可以不同，但主程序不能更改，输入输出严格按照要求来。输出要求：整数输出不能带小数点；不能输出2.3000，应是2.3；不能输出000123.3，应是123.3，总之符合正常书写格式。

-Through the process of large numbers exponentiation. Requirements in accordance with the operator overloading version class declaration can be different, but the main program can not be changed, the input and output in strict accordance with the requirements. Output requirements: Integer output can not be a decimal point　can not output 2.3000 2.3　can not output 000,123.3 123.3, in short, in line with normal writing format.