MS Visual C ++ 2010 Express继续运行旧代码

I'm using MS Visual C++ 2010 Express. When I want to run a program, it only works the first time. With this I mean that after I run it for the first time, and change my code all together and then try to run it again, it just keeps running my old code. How can I prevent this from happening?I'm using MS Visual C++ 2010 Express. When I wa