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Cyclomatic Complexity Dan Fleck Fall 2007 What is it? A software metric used to measure the complexity of software Developed by Thomas McCabe Described (informally) as the number of decision points + 1 Cyclomatic Complexity V(G) Computing the cyclomatic complexity: number of simple decisions + 1 or number of enclosed areas + 1 In this case, V(G) = 4 From Pressman Slides - Software Engineering a Practical Approach 6,e Graph Complexity (Cyclomatic Complexity) A number of industry studies have indicated that the higher V(G), the higher the probability or errors. modules V(G) modules in this range are more error prone From Pressman Slides - Software Engineering a Practical Approach 6,e Basis Path Testing Next, we derive the independent paths: 1 Since V(G) = 4, there are four paths 2 3 4 5 7 8 6 Path 1: Path 2: Path 3: Path 4: 1,2,3,6,7,8 1,2,3,5,7,8 1,2,4,7,8 1,2,4,7,2,4,...7,8 Finally, we derive test cases to exercise these paths. From Pressman Slides - Software Engineering a Practical Approach 6,e What is the complexity? public void howComplex() { int i=20; while (i<10) { System.out.printf("i is %d", i); if (i%2 == 0) { System.out.println("even"); } else { System.out.println("odd"); } } } What is the complexity V(G)? public void howComplex() { int i=20; while (i<10) { System.out.printf("i is %d", i); if (i%2 == 0) { System.out.println("even"); } else { System.out.println("odd"); } } } V(G) = 2 enclosed area + 1 = 3 Output from JavaNCSS