这是一个计算器的程序, 我花了半个小时写出来的, 虽然我还可以下载200多个, 但还是上传一个上去. 写得不是很好,请大家见谅.-This is a calculator program, I spent a half an hour to write out, although I can also download more than 200, but still upload a go. Written not very good, please forgive me ev