ECE 264 Object-Oriented Software Development Instructor: Dr. Honggang Wang Fall 2012 Lecture 2: Software Design Cycle

Lecture outline Announcements/reminders  For MSDN account, Andrew Smart MUST contact Andrew using your UMassD Non majors can use MS DreamSpark ( Quick review of pretest Software design cycle  General overview Software engineering steps Types of testing 6/3/2016 ECE 264: Lecture 2 2

6/3/2016 ECE 264: Lecture 2 3 Pretest review Pretest intended to review the following  Control structures (if/else, switch, loops)  Basic data types  Array accesses  C output First three topics use exactly the same syntax in C++! We’ll cover C++ output starting in lecture 3

Pretest review: if/else statements int x, y;. if (x < 5) { y = x + 1; } else { y = x – 2; } 1. At the end of the if/else statement above, if x = 4, y is equal to: a. 1b. 2 c. 4d Now, if x = 5, y is equal to: a. -2b. 3 c. 5d. 6 6/3/2016 ECE 264: Lecture 2 4

Pretest review: loops int x = 1; int i = 0; while (i <= 3) { x = x * 2; i++; } 3. Fill in the blank: The body of the while loop executes ______ times. a. 2b. 3 c. 4 d. an infinite number of 4. The final value of x is: a. 2b. 3 c. 8 d Which of the following is a for loop that can replace the while loop and produce the same result for x? a. for (i = 1; i < 4; i++) b. for (i = 0; i < 3; i++) c. for (x = 0; x <= 3; x++) d. for (i = 3; i >= 0; i--) 6/3/2016 ECE 264: Lecture 2 5

Pretest review: arrays, I/O int A[5] = {0, 7, 13, 12, 5}; for (i = 0; i < 5; i++) { printf(“A[%d] + 3 = %d\n”, i, A[i] + 3); } 6. In the first iteration, the program will display the following text on the screen: a. A[%d] + 3 = %d\n b. A[i] + 3 = A[i] + 3 c. A[0] + 3 = 3 d. A[1] + 3 = The value of A[4] is: a. 4 b. 5 c. 12 d. non-existent 6/3/2016 ECE 264: Lecture 2 6

Pretest review: switch statements switch (var) { case 0: case 1: x = x + var; break; case 2: x = x – var; case 3: x = x * var; break; default: x = var; } Assume x always equals 5 at the start of the switch statement. What is the value of x at the end of the statement if: 8. var = 1? a. 1b. 4 c. 5 d var = 2? a. 2b. 3 c. 6 d var = 5? a. 0 b. 5 c. 10 d. 25 6/3/2016 ECE 264: Lecture 2 7

Software design cycle Software engineering: application of systematic approach to development, operation, and maintenance of software  Not just programming!  Lots of management involved Traditional software design cycle  Requirements engineering  Design  Programming  Integration  Delivery  Maintenance 6/3/2016 ECE 264: Lecture 2 8

Software engineering cycle phases Requirements: Client needs  Translate these into requirements specification Design:  Developers translate requirements to actual product  Iterative process Start with broad outline: what’s the overall functionality we need? Break that down into smaller pieces: what modules are needed? What details are needed for each module? How do modules interact? Final result of this stage: design specification Can include  Verbal description of design, both at high & low level  UML diagrams showing varying levels of detail about project 6/3/20169 ECE 264: Lecture 2

Software engineering cycle phases (cont.) Programming: Write the actual code  Translate the design spec into language of choice  May have multiple programmers handling different modules Integration: Merge modules together  The different pieces of software are merged together. Testing is crucial in this phase to ensure the software works and meets all the requirements of the clients. Delivery: Get product to client  Client typically conducts acceptance testing to ensure product meets requirements Maintenance:  Fix remaining bugs  Modify product to meet new requirements 6/3/ ECE 264: Lecture 2

Testing Testing is key from design stage on  Unit testing: does a given module function in the expected manner? You use unit testing every time you debug an individual method, class, etc.  Integration testing: do modules fit together? Multiple functions calling one another; compatibility among classes; merging files from different parts of the program  System testing: does whole system work together?  Acceptance testing: user-designed tests with developer support to ensure product meets requirements Good idea to formulate testing plans in design stage  As you determine design spec, think about how you’re going to test your software 6/3/2016 ECE 264: Lecture 2 11

Final notes Next time Use case modeling Requirements specifications Introduce C++ basics Acknowledgements: this lecture borrows heavily from lecture slides provided with the following texts: Deitel & Deitel, C++ How to Program, 8 th ed. Etter & Ingber, Engineering Problem Solving with C++, 2 nd ed. 6/3/2016 ECE 264: Lecture 2 12