CSE360 Lecture 25

Introduction to Software Engineering
Software Measurement II
(201806)

Transcript

1. CSE360 Introduction to Software Engineering Lecture 25: Software Metrics II Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu Office Hours: By appointment
2. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 2 Function Metrics • Average LOC per Function Metric. An accepted industry standard of 200 LOC per function is desired as the average LOC per function • Maximum LOC per Function Metric. • Minimum LOC per Function Metric. A minimum LOC per function of 2 or less can indicate functions that may have been prototype but not yet complete..
3. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 3 Function Metrics • Cyclomatic Complexity. It is a quantitative measure of the number of linearly independent paths • Paths occurs when a "while", "for", "if", "case" and "goto" keywords appear within the function. • if the source code contained no control flow statements (conditionals or decision points), the complexity would be 1 • If the code had one single-condition IF statement, there would be 2 paths through the code: one where the IF statement evaluates to TRUE and another one where it evaluates to FALSE • Two nested single-condition IFs, or one IF with two conditions, would produce a complexity of 3.
4. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 4 Cyclomatic Complexity CC = Edge - Node + 2 Or CC = ConditionalNodes + 1
5. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 5 Cyclomatic Complexity i = 0; n=4; while (i<n-1) { j = i + 1; while (j<n) { if (A[i]<A[j]) swap(A[i], A[j]); } i=i+1; } // CC = 9 - 7 + 2 = 4 // CC = 3 + 1 = 4 (Condition nodes are 1,2 and 3 nodes) // A set of possible execution path of a program // 1, 7 // 1, 2, 6, 1, 7 // 1, 2, 3, 4, 5, 2, 6, 1, 7 // 1, 2, 3, 5, 2, 6, 1, 7
6. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 6 Cyclomatic Complexity Complexity Number Meaning 1-10 Structured and well written code High Testability Cost and Effort is less 10-20 Complex Code Medium Testability Cost and effort is Medium 20-40 Very complex Code Low Testability Cost and Effort are high >40 Not at all testable Very high Cost and Effort
7. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 7 Example A (Week 05) • 3 files • 24 methods • 394 lines • 326 LOC • 285 eLOC • 182 lLOC • 20 Lcomments • Comments 5.1% • Blank lines 12.2% • Spaces: 21.0% (79% code) • Max CC: 6 • Average CC: 1.46 • Total P: 18 • Max P: 3 • Average P: 0.75 • Total R: 25 • Max R: 2 • Average R: 1.04
8. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 8 Example A (Week 05)
9. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 9 Example B (Week 05) • 5 files • 21 methods • 522 lines • 412 LOC • 356 eLOC • 276 lLOC • 72 Lcomments • Comments 13.8% • Blank lines 7.3% • Spaces: 26.7% (73.3% code) • Max CC: 7 • Average CC: 2.24 • Total P: 34 • Max P: 7 • Average P: 1.62 • Total R: 21 • Max R: 1 • Average R: 1
10. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 10 Example B (Week 05)
11. Javier Gonzalez-Sanchez | CSE360 | Summer 2017 | 11 Reference Chapter 24
12. CSE360 – Introduction to Software Engineering Javier G onzalez-Sanchez javiergs@ asu.edu Sum m er 2017 Disclaim er. These slides can only be used as study m aterial for the class C SE360 at ASU. They cannot be distributed or used for another purpose.