3 Keywords in C++

My teacher today in CS had some funny comments in class. This is a data structures class in C++. We have a project due in a week and a half, and everyone was asking questions about what we are allowed to use or do on the project. Some things came up like multiple inheritance, and other generalized features of the language. He said that he would allow all uses of the STL, any features of the language, except for 3 ...