Calculate Cyclomatic complex when it comes to a recursion function

Question

Traditionally, Cyclomatic Complexity(CC) can be obtained by using the way that the number of "if-else" and then plus one. But when it comes to a recursion function, I found I unable to figure out the number of "if-else". More specifically, in this code block

public int m1(int k){
    if(k==0)
        return 0;
    else
        return m2(k-1)+(k%2);
}

public int m2(int k){
    if(k==0)
        return 0;
    else
        return m1(k-1)+(1-k%2);
}

How can I determine the CC of m1?

Explanation:

define a function CC(func) which stands for the CC of the function "func"

So, CC(m1) = 1(k==0) + CC(m2) (k!=0)

And CC(m2) = 1(k==0) + CC(m1) (k!=0)

I mean, we should take the CC of functions invoked into account.

Thanks for your help.

You're asking how many if/else statements are in `m1`? Couldn't you count it yourself? Or are you asking how many times it will execute? — Vince, Jun 10 '18 at 04:33

gargkshitiz · Accepted Answer · 2018-06-12T10:01:41.470

2

See https://en.m.wikipedia.org/wiki/Cyclomatic_complexity. Recursion by definition does not impact cyclomatic complexity and the tools measuring it also do not actually 'run' the code and measure it. This is because the original definition of McCabe states that CC is the number of possible path that the code can take, and that's about it. If you are still not convinced , just give it a different name, say recursive cylcomatic complexity, and measure it, by counting the actual number of invocations at runtime. Refer: https://www.guru99.com/cyclomatic-complexity.html

edited Jun 12 '18 at 10:01

answered Jun 10 '18 at 04:50

gargkshitiz

2,130
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So, the control flow graph is like this way [graph](https://ibb.co/hLzPf8) And, the CC of m1 is 3? – Spica Jun 10 '18 at 05:00
could you please accept this as an answer and upvote , if it helped? – gargkshitiz Jun 12 '18 at 10:01

Calculate Cyclomatic complex when it comes to a recursion function

1 Answers1