PPT6: Scientific debugging CEN 4072 Software Testing PPT6: Scientific debugging PPT and video are due: no later than October 5, 5:00 PM Submit to: lpiegl@gmail.com This template file is just an outline of the presentation that you need to complete. Additional pages will be necessary to fully explore the topic above. Each page should contain adequate text as well as illustrations. You are free to use all publically available information (text as well as graphics) as long as the sources are properly acknowledged.

Team members’ contributions Member [name]:

Errors Content outline: What is an error in the software

Causes and effects Content outline: What is the cause of a problem? Examples

Causes and effects Content outline: How to prove causality? Example

Causality Content outline: Repeating history Can we repeat history in software?

Causality Content outline: Repeating program runs How much data and knowledge does it take?

Causes by intuition Content outline: Can intuition be taught? What is tacit knowledge and how one would acquire it?

Scientific method: what is it? Content outline: Explanation and examples

Scientific method: main steps Content outline: Steps and their explanations in using the scientific method

What is a theory? Content outline: The road from hypothesis to theory

Scientific method of debugging Content outline: Details, explanation and chart

Sample program revisited int main(int argc, char *argv[]) { int *a; int i; a = (int *)malloc((argc - 1) * sizeof(int)); for (i = 0; i < argc - 1; i++) a[i] = atoi(argv[i + 1]); shell_sort(a, argc); printf("Output: "); printf("%d ", a[i]); printf("\n"); free(a); return 0; } static void shell_sort(int a[], int size) { int i, j; int h = 1; do { h = h * 3 + 1; } while (h <= size); h /= 3; for (i = h; i < size; i++) int v = a[i]; for (j = i; j >= h && a[j - h] > v; j -= h) a[j] = a[j - h]; if (i != j) a[j] = v; } } while (h != 1);

Debugging with the scientific method Content outline: Detailed steps of how to use the scientific method to debug the sample program

Explicit debugging Content: Stating the problem explicitly can help solve the problem The Teddy Bear principle of software

Keep a notebook Content outline: Keep a record of each debugging session

Algorithmic debugging Content outline: Steps of the algorithmic debugging

Example code for algorithmic debugging def insert(elem, list): if len(list) == 0: return [elem] head = list[0] tail = list[1:] if elem <= head: return list + [elem] return [head] + insert(elem, tail) def sort(list): if len(list) <= 1: return list head = list[0] tail = list[1:] return insert(head, sort(tail))

Algorithmic debugging session Content outline: Step-by-step debugging of the sample code above Include an explanation as well as a chart

Pros and Cons Content outline: Pros and cons of the scientific debugging

Obtaining a hypothesis Content outline: Observing a run Deducing from the code Problem report Earlier hypotheses

Reasoning about the programs: deduction Content outline: Details on how to use deduction Example

Reasoning about the programs: observation Content outline: Details on how to use observation Example

Reasoning about the programs: induction Content outline: Details on how to use induction Example

Reasoning about the programs: experimentation Content outline: Details on how to use experimentation Example

Your code experimentations Content outline: Share your experience(s) with experiments Examples