验证命令行参数的数量

I am trying to validate that there are only three arguments passed. In this program I am looking to pass two integers using command line arguments that look like 23 23 +. But I want an error to display if they enter less than three arguments or more than three arguments. As is right now, it gives the error message when there is more than three arguments but not less than three. Any help would be great please.I am trying to validate that there are only thr