Cyclomatic Complexity Measures

Cyclomatic  Complexity Measures:

McCabe proposed the cyclomatic number, V (G) of graph theory as an indicator of software complexity. The cyclomatic number is equal to the number of linearly independent paths through a program in its graph representation.

Cyclomatic complexity can be used in two ways, to:

• Limit code complexity.
• Determine the number of test cases required.

Cyclomatic complexity can be one of the most difficult software quality metrics to understand. And that makes it difficult to calculate.

 For a program control graph G, cyclomatic number, V (G), is given as:

              V (G) = E - N + 2 * P

E = The number of edges in graphs G

N = The number of nodes in graphs G

P = The number of connected components in graph G.

Properties:

1. V (G) is the maximum number of independent paths in the graph
2. V (G) >=1
3. G will have one path if V (G) = 1
4. Minimize complexity to 10

Example:

Another Example:

Advantages:

• Gives complexity of various designs
• Computed early in life cycle
• Easy to apply
• Measures minimum effort

Disadvantages: 

• Measures program’s control complexity and not the data complexity
• Nested conditional structures are harder to understand
• Ignore the size of the program