按照组件化程序设计方法，用Visual C++编写实现包含ICalculate、IMul、IStr三个接口的.dll组件，并利用客户端应用程序完成对各接口的充分测试。-Using Visual C++ implementation of ICalculate, IMul, IStr contains three interface . DLL components, and the use of the client application to complete the full test i