Programming Abstractions in C++ by Eric S. Roberts 的作业2，斯坦福原创题，我自己写完的。-Programming Abstractions in operating C++ by Eric S. Roberts, Stanford, original title, finished by myself.

Programming Abstractions in C++ by Eric S. Roberts 的作业1，斯坦福原创题，finished by myself-Programming Abstractions in C++ jobs by Eric S. Roberts 1, Stanford original title, finished is by myself