spaghetti code

Code that overuses GOTO statements rather than structured programming constructs, resulting in convoluted and unmaintainable programs, is often called spaghetti code.{{cite journal|last1=Cram|first1=David|last2=Hedley|first2=Paul|title=Pronouns and procedural meaning: The relevance of spaghetti code and paranoid delusion|journal=Oxford University Working Papers in Linguistics, Philology and Phonetics|date=2005|volume=10|pages=187–210|url=http://mostlyharmless.org.uk/wp-content/uploads/2010/12/cramhedley-web.pdf|access-date=5 March 2018|archive-date=6 March 2018|archive-url=https://web.archive.org/web/20180306022905/http://mostlyharmless.org.uk/wp-content/uploads/2010/12/cramhedley-web.pdf|url-status=dead}}

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.{{cite book|last1=Horstmann|first1=Cay|title=Java Concepts for AP Computer Science|date=2008|publisher=J. Wiley & Sons|location=Hoboken, NJ|isbn=978-0-470-18160-7|pages=235–236|edition=5th ed. [i.e. 2nd ed.].|chapter-url=http://horstmann.com/bigjava3.html|access-date=2 January 2017|language=en|chapter=Chapter 6 - Iteration}}

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".{{cite book|title=ASTM special technical publication|issue=500–565|author=United States National Bureau of Standards|publisher=United States Government Printing Office|year=1980}}

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.{{cite journal|last1=Moha|first1=N.|last2=Gueheneuc|first2=Y. G.|last3=Duchien|first3=L.|last4=Meur|first4=A. F. Le|title=DECOR: A Method for the Specification and Detection of Code and Design Smells|journal=IEEE Transactions on Software Engineering|date=January 2010|volume=36|issue=1|pages=20–36|doi=10.1109/TSE.2009.50|issn=0098-5589|citeseerx=10.1.1.156.1524|s2cid=14767901}} The presence of this form of spaghetti code can significantly reduce the comprehensibility of a system.{{cite book|last1=Abbes|first1=M.|last2=Khomh|first2=F.|last3=Gueheneuc|first3=Y. G.|last4=Antoniol|first4=G.|title=2011 15th European Conference on Software Maintenance and Reengineering |chapter=An Empirical Study of the Impact of Two Antipatterns, Blob and Spaghetti Code, on Program Comprehension |date=2011|pages=181–190|doi=10.1109/CSMR.2011.24|isbn=978-1-61284-259-2|citeseerx=10.1.1.294.1685|s2cid=14152638}}

It is not clear when the phrase spaghetti code came into common usage; however, a references appeared in 1972 including The principal motivation behind eliminating the goto statement is the hope that the resulting programs will not look like a bowl of spaghetti. by Martin Hopkins.Hopkins, M. E. (1972): A Case fo the GOTO. In: ACM '72: Proceedings of the ACM annual conference - Volume 2, August 1972, pp 787–790, p 59 DOI:https://dl.acm.org/doi/10.1145/800194.805860 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",{{cite book|title=A primer on disciplined programming using PL/I, PL/CS, and PL/CT|last=Conway|first=Richard|publisher=Winthrop Publishers|year=1978|isbn=978-0-87626-712-7}} a phrase repeated in the 1979 book An Introduction to Programming he co-authored with David Gries.{{cite book|title=An Introduction to Programming|last1=Conway|first1=Richard|last2=Gries|first2=David|edition=3rd|publisher=Little, Brown|year=1979|isbn=978-0-316-15414-7}} 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.{{cite journal|journal=IEEE Computer|title=A spiral model of software development and enhancement|last=Boehm|first=Barry W.|volume=21|issue=2|date=May 1988|pages=61–72|doi=10.1109/2.59|s2cid=1781829}} 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.{{cite book|title=Structured programming for the COBOL programmer: design, documentation, coding, testing|last=Noll|first=Paul|publisher=M. Murach & Associates|year=1977}}

In the Ada – Europe '93 conference, Ada was described as forcing the programmer to "produce understandable, instead of spaghetti code", because of its restrictive exception propagation mechanism.{{cite conference|conference=Ada – Europe '93 (Proceedings)|book-title=Lecture Notes in Computer Science|title=Use and abuse of exceptions — 12 guidelines for proper exception handling|last=Schwille|first=Jürgen |series=Lecture Notes in Computer Science |volume=688|year=1993|publisher=Springer Berlin Heidelberg|pages=142–152|doi=10.1007/3-540-56802-6_12|isbn=978-3-540-56802-5 }}

In a 1981 computer languages spoof in The Michigan Technic titled "BASICally speaking...FORTRAN bytes!!", the author described FORTRAN stating that "it consists entirely of spaghetti code".{{cite journal|journal=The Michigan Technic|title=BASICally speaking...FORTRAN bytes!!|author=MTSBS{{clarify|date=April 2015}}|

volume=99|issue=4|date=March–April 1981}}

Richard Hamming described in his lectures{{cite book |last1=Hamming |first1=Richard |title=The Art of Doing Science and Engineering |date=1996 |publisher=Taylor & Francis |isbn=9056995006}} the etymology of the term in the context of early programming in binary codes:

{{Quote

|text=If, in fixing up an error, you wanted to insert some omitted instructions then you took the immediately preceding instruction and replaced it by a transfer to some empty space. There you put in the instruction you just wrote over, added the instructions you wanted to insert, and then followed by a transfer back to the main program. Thus the program soon became a sequence of jumps of the control to strange places. When, as almost always happens, there were errors in the corrections you then used the same trick again, using some other available space. As a result the control path of the program through storage soon took on the appearance of a can of spaghetti. Why not simply insert them in the run of instructions? Because then you would have to go over the entire program and change all the addresses which referred to any of the moved instructions! Anything but that!

}}

Ravioli code is a term specific to object-oriented programming. It describes code that comprises well-structured classes that are easy to understand in isolation, but difficult to understand as a whole.{{cite conference|last1=De Troyer|first1=O.|title=The OO-binary relationship model : A truly object oriented conceptual model|conference=Advanced Information Systems Engineering|volume=498|date=13 May 1991|pages=561–578|doi=10.1007/3-540-54059-8_104|language=en|series=Notes on Numerical Fluid Mechanics and Multidisciplinary Design|isbn=978-3-319-98176-5|s2cid=10894568 |editor-last=Andersen |editor-first=Rudolf|editor2-last=Bubenko |editor2-first=Janis A. |editor3-last=Sølvberg |editor3-first=Arne|url=https://pure.uvt.nl/ws/files/5292185/DTO5613576.pdf}}

{{See also|Architectural layer|Layer (object-oriented design)}}

Lasagna code refers to code whose layers are so complicated and intertwined that making a change in one layer would necessitate changes in all other layers.{{cite journal|last1=Tomov|first1=Latchezar|last2=Ivanova|first2=Valentina|title=Teaching Good Practices In Software Engineering by Counterexamples|journal=Computer Science and Education in Computer Science|date=October 2014|issue=1|pages=397–405|url=https://www.researchgate.net/publication/301298530|access-date=5 March 2018}}

Here follows what would be considered a trivial example of spaghetti code in BASIC. The program prints each of the numbers 1 to 100 to the screen along with its square. Indentation is not used to differentiate the various actions performed by the code, and the program's GOTO statements create a reliance on line numbers. The flow of execution from one area to another is harder to predict. Real-world occurrences of spaghetti code are more complex and can add greatly to a program's maintenance costs.

1 i=0

2 i=i+1

3 PRINT i;"squared=";i*i

4 IF i>=100 THEN GOTO 6

5 GOTO 2

6 PRINT "Program Completed."

7 END

Here is the same code written in a structured programming style:

1 FOR i=1 TO 100

2 PRINT i;"squared=";i*i

3 NEXT i

4 PRINT "Program Completed."

5 END

The program jumps from one area to another, but this jumping is formal and more easily predictable, because for loops and functions provide flow control whereas the goto statement encourages arbitrary flow control. Though this example is small, real world programs are composed of many lines of code and are difficult to maintain when written in a spaghetti code fashion.

Here is another example of spaghetti code with embedded GOTO statements.

INPUT "How many numbers should be sorted? "; T

DIM n(T)

FOR i = 1 TO T

PRINT "NUMBER:"; i

INPUT n(i)

NEXT i

'Calculations:

C = T

E180:

C = INT(C / 2)

IF C = 0 THEN GOTO C330

D = T - C

E = 1

I220:

f = E

F230:

g = f + C

IF n(f) > n(g) THEN SWAP n(f), n(g)

f = f - C

IF f > 0 THEN GOTO F230

E = E + 1

IF E > D THEN GOTO E180

GOTO I220

C330:

PRINT "The sorted list is"

FOR i = 1 TO T

PRINT n(i)

NEXT i

{{Portal|Computer programming|Engineering}}

• Big ball of mud, a piece of software with no perceivable architecture
• International Obfuscated C Code Contest, a competition to produce pleasingly obscure C code
• Technical debt
• The Elements of Programming Style

{{Reflist}}

• [http://portal.acm.org/citation.cfm?id=362929.362947 Go To Statement Considered Harmful]. The classic repudiation of spaghetti code by Edsger Dijkstra
• [http://www.fortran.com/fortran/come_from.html We don't know where to GOTO if we don't know where we've COME FROM by R. Lawrence Clark from DATAMATION, December, 1973] {{Webarchive|url=https://web.archive.org/web/20180716171336/http://www.fortran.com/fortran/come_from.html |date=2018-07-16 }}
• [http://yost.com/computers/java/java-spaghetti/ Refactoring Java spaghetti code into Java bento code] separating out a bowl full of code from one class into seven classes
• [https://archive.today/20130201082958/http://www.remotesynthesis.com/post.cfm/Objects-and-Frameworks--Taking-a-Step-Back Objects and Frameworks – Taking a Step Back] by Brian Rinaldi
• [https://blog.docsity.com/en/study-tips/programming-2/programming-pasta-spaghetti-lasagna-ravioli-macaroni-code/ Programming Pasta - Spaghetti, Lasagna, Ravioli and Macaroni Code] {{Webarchive|url=https://web.archive.org/web/20230121050907/https://blog.docsity.com/en/study-tips/programming-2/programming-pasta-spaghetti-lasagna-ravioli-macaroni-code/ |date=2023-01-21 }}
• [https://www.techopedia.com/definition/24994/pasta-theory Pasta Theory of Programming]

Category:Anti-patterns

Category:Articles with example BASIC code

Category:Software engineering folklore

Category:Pejorative terms related to technology

Category:Metaphors referring to spaghetti