hsxfjames Long story short, decision points are any constructs that can alter the normal flow of control in the program. So for a standard calculation flow of cyclomatic complexity, there are several steps:
Identify the control flow graph (CFG) of the program. A control flow graph is a graphical representation of the program's control flow, which shows the sequence of instructions executed in the program.
Calculate the cyclomatic complexity using the formula:
M = E - N + 2
M is the cyclomatic complexity
E is the number of edges in the CFG
N is the number of nodes in the CFG
For the loop, it usually contributes a decision point, because either you continue the loop or you go to the next expression.
For the CFG, it is a big topic, maybe Control-flow-graph-wikipedia can explain it better than me.