Calculate the CC (Cyclomatic Complexity) of the following code snippets.
I am not sure if I have drawn the Control Flow Graph correctly and furthermore if my calculation for the Cyclomatic Complexity is correct. And as for the formula M = E - N + 2P, the P is defined as "P = number of nodes that have exit points". Am I only counting the return here? How is it then with GCD2, if the method calls itself recursively does this also count as a return?
GCD1
public class GCD1 {
public int gcd(int a, int b) {
if (a < b) {
int t = a;
a = b;
b = t;
}
while (a % b != 0) {
int r = a % b;
a = b;
b = r;
}
return b;
}
}
GCD2
public class GCD2 {
public int gcd(int a, int b) {
if (a < b)
return gcd(b, a);
else if (b == 0)
return a;
else
return gcd(b, a % b);
}
}
Calculation
M = E – N + 2P
where,
- E = the number of edges in the control flow graph
- N = the number of nodes in the control flow graph
- P = number of nodes that have exit points
Control Flow Graph of above GCD1
M = 7 - 6 + 2*1 = 3
Control Flow Graph of above GCD2
M = 8 - 7 + 2*1 = 3
