能实现的简单四则运算，包括有加，减，乘，除等运算。-To achieve a simple four operations, including addition, subtraction, multiplication, addition, etc. op.

在java环境下实现计算器,实现加减乘除各种运算！优点是方便快捷,(Realize the calculator in the Java environment, all kinds of operation implement addition, subtraction, multiplication, and division.)