Part of the code of the computer game Cold Blood.
Copyright primarily protects the written code of a computer program . The established interpretation is that both, source code and its translated machine language, as well as their intermediate forms, can be protected by copyright if they exceed the required level of originality . The way in which the code is held is not relevant from the copyright's perspective. Thus, code that is held in a book, file or circuit board is, as a rule, protected by copyright on the same basis.
`However, not all codes are protected by copyright. Copyright extends only to expressions and not the ideas behind them. Monopolization of ideas and principles would hinder the software industry and obstruct progress. Thus, parts of code that are based on ideas cannot be protected by copyright. For example, the logical principles and algorithms of a program, and the syntax and semantics of a programming language are not protected by copyright in so far as they are considered ideas and principles.
Which expressions then are protected, and which are not? According to the established interpretation in case law in the United States, code that can be expressed in only one way cannot be protected by copyright. In addition, all expressions that are necessary to realize an idea are considered to constitute parts of the idea that is not protected by copyright. Thus, the mechanical resolution of a problem is usually not protected by copyright.
Notes and References
 KM 1987:8
 HE 161/1990 vp.