How to detect code duplication during development? [closed]

Answer 1

duplo appears to be a C implementation of the algorithm used in Duploc. It is simple to compile and install, and while the options are limited it seems to more or less work out-of-the-box.

Answer 2

CCFinderX is a free (for in-house use) cloned code detector that supports multiple programming languages (Java, C, C++, COBOL, VB, C#).

Answer 3

You can use our SourceMeter tool for detecting code duplication. It is a command line tool (very similar to compilers), so you can it easily integrate into continuous integration tools, like CruiseControl your mentioned, or Jenkins.

Answer 4

Well, you can run a clone detector on your source code base every night.

Many clone detectors work by comparing source lines, and can only find exact duplicate code.

CCFinder, above, works by comparing language tokens, so it isn't sensitive to white space changes. It can detect clones which are variants of the original code if there only single token changes (e.g, change a variable X to Y in the clone).

Ideally what you want is the above, but the ability to find clones where the variations are allowed to be relatively arbitrary, e.g., replace a variable by an expression, a statement by a block, etc.

Our CloneDR clone detector does this for Java, C#, C++, COBOL, VB.net, VB6, Fortran and a variety of other languages. It can be seen at: http://www.semdesigns.com/Products/Clone/index.html

As well as being able to handle multiple languages, CloneDR engine is capable of handling a variety of input encoding styles, including ASCII, ISO-8859-1, UTF8, UTF16, EBCDIC, a number of Microsoft encodings, and (Japanese) Shift-JIS.

The site has several clone detection run example reports, including one for C++.

EDIT Feb 2014: Now handles all of C++14.

Answer 5

Finding "identical" code snippets is relatively easy, there are existing tool that already do this (see other answers).

Sometimes it's a good thing, sometimes it's not; it can bog down development time if done at a too fine "level"; i.e. trying to refactor so much code, you loose your goal (and probably bust your milestones and schedules).

What is harder is to find multiple function/method that do the same thing but with different (but similar) inputs and/or algorithm without proper documentation.

If you have to two or different methods to do the same thing and the programmer try to fix one instance but forget (or does not know they exist) to fix the other ones, you will increase the risk to your software.

Answer 6

Simian detects duplicate code in C++ projects.

Update: Also works with Java, C#, C, COBOL, Ruby, JSP, ASP, HTML, XML, Visual Basic, Groovy source code and even plain text files