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-consider-switch-as-single-decision

Compute cyclomatic complexity assuming a switch-case statement to be a single decision point

Syntax

-consider-switch-as-single-decision

Description

-consider-switch-as-single-decision changes how Polyspace® calculates the metric Cyclomatic Complexity and the Guideline Cyclomatic complexity exceeds threshold. Cyclomatic complexity is the number of decision points in your code plus one. By default, Polyspace counts each individual case of a switch-case statement as a separate decision point if the case if terminated with a break statement. When you specify this option, Polyspace counts the entire switch-case statement as a single decision point.

Examples

Change in Value of Cyclomatic Complexity

In this example, the function factorial() selects a return value using a switch-case statement.

int factorial(int in) {
	int val = -1;
	switch(in) {
		case 1:
			val = 1;
			break;
		case 2:
			val = 2;
			break;
		case 3:
			val = 6;
			break;
		default:
			break;
	}
	return val;
}
By default, Polyspace reports the value of Cyclomatic Complexity as 4. When you specify this option, Polyspace considers the entire switch-case statement as a single decision point, resulting in a cyclomatic complexity of 2.

Change in Guideline Rule Violation

In this example, The cyclomatic complexity of factorial() is 8, which is above the specified threshold 5, resulting in a violation of the guideline Cyclomatic complexity exceeds threshold.

int factorial(int in) { //Noncompliant
	int val = -1;
	switch(in) {
		case 1:
			val = 1;
			break;
		case 2:
			val = 2;
			break;
		case 3:
			val = 6;
			break;
		case 4:
			val = 24;
			break;
		case 5:
			val = 120;
			break;
		case 6:
			val = 720;
			break;
		case 7:
			val = 5040;
			break;
		default:
			break;
	}
	return val;
}

When you specify the option -consider-switch-as-single-decision, the cyclomatic complexity becomes 2 and the guideline Cyclomatic complexity exceeds threshold is no longer violated.

Dependencies

This option is relevant when you calculate the code metrics or activate the Guidelines coding rules. See:

See Also

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