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Cyclomatic complexity is a software metric (measurement). It was developed by Thomas McCabe and is used to measure the complexity of a program. It directly measures the number of linearly independent paths through a program's source code. Image File history File links Mergefrom. ...
Essential complexity refers to a situation where all reasonable solutions to a problem must be complicated (and possibly confusing) because the simple solutions would not adequately solve the problem. ...
The complexity of most computer programs and programming languages is one of the unsolved problems in software engineering. ...
A software metric is a measure of some property of a piece of software or its specifications. ...
Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ...
The concept, although not the method, is somewhat similar to that of general text complexity measured by the Flesch-Kincaid Readability Test. The Flesch/Flesch–Kincaid Readability Tests are readability tests designed to indicate how difficult a reading passage is to understand. ...
Cyclomatic complexity is computed using a graph that describes the control flow of the program. The nodes of the graph correspond to the commands of a program. A directed edge connects two nodes if the second command might be executed immediately after the first command. In computer science control flow (or alternatively, flow of control) refers to the order in which the individual statements, instructions or function calls of an imperative or functional program are executed or evaluated. ...
Definition
- M = E − N + 2P
where - M = cyclomatic complexity
- E = the number of edges of the graph
- N = the number of nodes of the graph
- P = the number of connected components.
"M" is alternatively defined to be one larger than the number of decision points (if/case-statements, while-statements, etc) in a module (function, procedure, chart node, etc.), or more generally a system. In an undirected graph, a connected component or component is a maximal connected subgraph. ...
In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. ...
Look up Procedure in Wiktionary, the free dictionary. ...
For other uses, see System (disambiguation). ...
Separate subroutines are treated as being independent, disconnected components of the program's control flow graph.
Alternative definition - v(G) = e − n + p
- G is a program's flowgraph
- e is the number of edges (arcs) in the flowgraph
- n is the number of nodes in the flowgraph
- p is the number of connected components
Alternative way There is another simple way to determine the cyclomatic number. This is done by counting the number of closed loops in the flow graph, and incrementing that number by one.
i.e.
- M = Number of closed loops + 1
where - M = Cyclomatic number.
Implications for Software Testing - M is a lower bound for the number of possible paths through the control flow graph.
- M is an upper bound for the number of test cases that are necessary to achieve a complete branch coverage.
For example, consider a program that consists of two sequential if-then-else statements. if (c1) { f1(); } else { f2(); } if (c2) { f3(); } else { f4(); } - To achieve a complete branch coverage, two test cases are sufficient here.
- For a complete path coverage, four test cases are necessary.
- The cyclomatic number M is three, falling in the range between these two values, as it does for any program.
Code coverage is a measure used in software testing. ...
Code coverage is a measure used in software testing. ...
Etymology / Naming The name Cyclomatic Complexity is quite misleading for a programmer, as this metric does not only count cycles (loops) in the program. It is motivated by the number of different cycles in the program control flow graph, after having added an imagined branch back from the exit node to the entry node, see [McCabe76], p. 309.
A better name for popular usage would be Conditional Complexity, as "it has been found to be more convenient to count conditions instead of predicates when calculating complexity" [McCabe76], p. 315.
Key Concept The cyclomatic complexity of a section of source code is the count of the number of linearly independent paths through the source code. For instance, if the source code contained no decision points such as IF statements or FOR loops, the complexity would be 1, since there is only a single path through the code. If the code had a single IF statement containing a single condition there would be two paths through the code, one path where the IF statement is evaluated as TRUE and one path where the IF statement is evaluated as FALSE. In computer science control flow (or alternatively, flow of control) refers to the order in which the individual statements, instructions or function calls of an imperative or functional program are executed or evaluated. ...
Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ...
Cyclomatic complexity is normally calculated by creating a graph of the source code with each line of source code being a node on the graph and arrows between the nodes showing the execution pathways. As some programming languages can be quite terse and compact, a source code statement when developing the graph may actually create several nodes in the graph (for instance, when using the "?:" ternary conditional operator in C, C++, C# and Java). In mathematics, a ternary operation is any operation of arity three, that is, that takes three arguments. ...
C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ...
C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ...
The title given to this article is incorrect due to technical limitations. ...
Java language redirects here. ...
In general, in order to fully test a module all execution paths through the module should be exercised. This implies a module with a high complexity number requires more testing effort than a module with a lower value since the higher complexity number indicates more pathways through the code. This also implies that a module with higher complexity is more difficult for a programmer to understand since the programmer must understand the different pathways and the results of those pathways.
One would also expect that a module with higher complexity would tend to have lower cohesion (less than functional cohesion) than a module with lower complexity. The possible correlation between higher complexity measure with a lower level of cohesion is predicated on a module with more decision points generally implementing more than a single well defined function. However there are certain types of modules that one would expect to have a high complexity number, such as user interface (UI) modules containing source code for data validation and error recovery. In computer programming, cohesion is a measure of how strongly-related and focused the various responsibilities of a software module are. ...
See also In computing, the complexity trap refers to the ever-increasing trend to add more functionality to software and/or hardware, often at the cost of increased complexity. ...
A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ...
Programming redirects here. ...
In computer science control flow (or alternatively, flow of control) refers to the order in which the individual statements, instructions or function calls of an imperative or functional program are executed or evaluated. ...
This article or section does not adequately cite its references or sources. ...
Design predicates are a method, invented by Thomas McCabe, to quantify the complexity of the integration of two units of software. ...
In algebraic topology, the Euler characteristic is a topological invariant, a number that describes one aspect of a topological spaces shape or structure. ...
Software engineering (SE) is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software. ...
Software testing is the process used to measure the quality of developed computer software. ...
The Panopticode free software / open source project provides a standardized format for describing the structure of software projects and integrates Software metrics from several tools into that format. ...
Complexity in general usage is the opposite of simplicity. ...
External links - A Complexity Measure - McCabe's original paper (1976).
- Cyclomatic complexity - at Software Engineering Institute, Carnegie Mellon University
- Resource Standard Metrics Cyclomatic and Interface Complexity analysis tool for all OS and Languages - Available for limited free use, ideal for computer science courses.
- Python complexity - Journyx provides McCabe-like cyclomatic complexity analysis tools for analyzing Python code (which are written in Perl).
- lint_php: PHP cyclomatic complexity - provides McCabe-like cyclomatic complexity free online analysis for PHP code (the tool is written in PHP, as well, and can be downloaded for offline use).
- McCabe Software, Inc. - Founded by Cyclomatic Complexity inventor Thomas J. McCabe, McCabe Software, Inc. provides a suite of complexity analysis and test coverage tools with support for several programming languages.
- Compuware's Xpediter/DevEnterprise - provides Cyclomatic Complexity for COBOL and PL/I programs among other metrics
- Structure101 - Uses Cyclomatic Complexity as a basis for analyzing and rating the quality of your software architecture.
- CyVis - A Free Software Cyclomatic Complexity visualiser tool for software built using Java.
- C & C++ Code Counter - A Free Software for count various metric of code including Cyclomatic Complexity
- Article Some thoughts on Cyclomatic Complexity from From The Trench
- Perl::Metrics::Simple - An Open Source library for static analysis of Perl code, providing a number of metrics including an approximation of Cyclomatic Complexity for each subroutine/method..
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