What are some common metrics used for evaluating program complexity?

There are several common metrics used for evaluating program complexity. Some of these metrics include:

1. Cyclomatic Complexity: This metric measures the number of independent paths through a program. It helps in identifying the complexity of control flow within a program. A higher cyclomatic complexity indicates a higher level of complexity and potential for errors.

2. Halstead Complexity Measures: These measures are based on the number of unique operators and operands used in a program. They provide insights into the program's volume, difficulty, and effort required for implementation.

3. Lines of Code (LOC): This metric simply counts the number of lines of code in a program. While it is a straightforward measure, it can be misleading as it does not consider the complexity of the code.

4. Maintainability Index: This metric combines various factors such as cyclomatic complexity, lines of code, and code duplication to provide an overall measure of how maintainable a program is. A higher maintainability index indicates better maintainability.

5. McCabe's Complexity: Similar to cyclomatic complexity, McCabe's complexity measures the number of independent paths through a program. It helps in identifying the complexity of control flow and potential for errors.

6. Fan-in and Fan-out: Fan-in measures the number of functions or modules that call a particular function or module, while fan-out measures the number of functions or modules called by a particular function or module. Higher fan-in and fan-out values indicate higher complexity and potential dependencies.

7. Depth of Inheritance: This metric measures the number of levels in the inheritance hierarchy of a program. A higher depth of inheritance indicates a higher level of complexity and potential for code reuse issues.

These metrics provide quantitative measures to evaluate program complexity, helping developers and testers identify potential areas of improvement and assess the overall quality and maintainability of the code.