这份C#代码是一个计算器，类似于WINDOWS自带的那个功能，可能做的没有那个好，但个人觉得比较美观，建议初学者看，因为这份是我以前写的，从性能上来讲不太好。-The C# code is a calculator that comes with features similar to WINDOWS, it may not do that well, but people feel more beautiful and recommended for beginners to see, bec