Spaghetti code

Spaghetti code is a pejorative phrase for unstructured and difficult-to-maintain source code. Spaghetti code can be caused by several factors, such as volatile project requirements, lack of programming style rules, and software engineers with insufficient ability or experience. Code that overuses GOTO statements rather than structured programming constructs, resulting in convoluted and unmaintainable programs, is often called spaghetti code. Such code has a complex and tangled control structure, resulting in a program flow that is conceptually like a bowl of spaghetti, twisted and tangled. In a 1980 publication by the United States National Bureau of Standards, the phrase spaghetti program was used to describe older programs having "fragmented and scattered files". Spaghetti code can also describe an anti-pattern in which object-oriented code is written in a procedural style, such as by creating classes whose methods are overly long and messy, or forsaking object-oriented concepts like polymorphism. The presence of this form of spaghetti code can significantly reduce the comprehensibility of a system. It is not clear when the phrase spaghetti code came into common usage; however, several references appeared in 1977 including Macaroni is Better Than Spaghetti by Guy Steele. In the 1978 book A primer on disciplined programming using PL/I, PL/CS, and PL/CT, Richard Conway described programs that "have the same clean logical structure as a plate of spaghetti", a phrase repeated in the 1979 book An Introduction to Programming he co-authored with David Gries. In the 1988 paper A spiral model of software development and enhancement, the term is used to describe the older practice of the code and fix model, which lacked planning and eventually led to the development of the waterfall model. In the 1979 book Structured programming for the COBOL programmer, author Paul Noll uses the phrases spaghetti code and rat's nest as synonyms to describe poorly structured source code.