An old study code targetted at sorting and cataloging PDF files in a computer. It s written in Visual Basic, a lot of sample codes from other places are also included. -An old study code targetted at sorting and cataloging PDF files in a computer. It

计算器，实现基本计算功能，还能实现托盘功能-Calculator, for basic computing functions, but also achieve the tray functionality

实现了一个简单的计算器程序，有基本的计算功能-Implements a simple calculator program, a basic calculation function