软件工程复习题(1).doc

1. Explain following terms concisely(1) Waterfall model(CH2)(2) Requirement validation and verification(CH4)(3) Agile methods(CH2)(4) COTS(CH1)(5) Critical path method(CPM)(CH3)(6) Cohesion and coupling(CH5)(7) Delivering the system(CH10)(8) CMM(CH3)(9) Prototype(CH2)(10) Extreme programming(XP)(CH2)(11) Programming style(CH7)(12) Software process(CH3)2. Enumerate some contents of given terminologies, give descriptions or examples if needed(1) Development phases(CH2)(2) Types of coupling(CH5)(3) Development Processes(CH2)(4) Types of Cohesion(CH5)(5) Logical covering approaches(CH8)(6) Integration approaches(CH8)3. Categorize or classifyIn an early meeting with your customer, the customer lists the following “requirements” for a system he wants you to build:(a) The client daemon must be invisible to the user(b) The system should provide automatic verification of corrupted links or outdated date(c) An internal naming convention should ensure that records are unique(d) Communication between the database and servers should be encrypted(e) Relationships may exist between title groups a type of record in the database(f) Files should be organizable into groups of file dependencies(g) The system must interface with an Oracle database(h) The system must handle 50,000 users concurrentlyClassify each of the above as a functional requirement, a quality requirement, a design constraint, or a process constraint. Which of the above might be premature design decisions? Re-express each of these decisions as a requirement that the design decision was meant to achieve.You have been hired by a computer consulting firm to develop an income tax calculation package for an accounting firm. You have designed a system according to the customers requirements and presented your design at a design review. Which of the following questions might be asked at the preliminary design review? At the critical design review? At both? Explain your answers.(a) What computer will it run on?(b) What will the input screens look like?(c) What reports will be produced?(d) How many concurrent users will there be?(e) Will you use a multiuser operating system?(f) What are the details of the depreciation algorithm?Categorize the following systems as S-, P- or E-systems. For each one, explain why it belongs in that category. Identify those aspects of the system that may change:(a) An air traffic control system(b) An operation system for a microcomputer(c) A floating-point acceleration system(d) A database management system(e) A system to find the prime factors of a number(f) A system to find the first prime number larger than a given number4. Answer the following questions(1) Explain the difference between errors, faults, and failures. Give an example of an error that leads to a fault in the requirements; the design; the code. Give an example of a fault in the requirements that leads to a failure; a fault in the design that leads to a failure; a fault in the test data that leads to a failure.(2) For each of the process models, how does the model handle a significant change in requirements late in development?(3) Does the McCabe cyclomatic number allow us to form an ordering of components according to quality? That is, can we always say that one component is more complex than another? Name some aspect of software complexity that are not captured by the cyclomatic number.(4) How does the description of a system relate to the notion of process models? For example, how do you decide what the boundary should be for the system described by a process model?(5) What kinds of performance tests might be required for a word processing system? A payroll system? An automated bank teller system? A water-quality monitoring system? A power plant control system?(6) Brooks says that adding people to a late project makes it even later (1975). Some schedule-estimation techniques seem to indicate that adding people to a project can shorten development time. Is this a contradiction? Why or why not?(7) For each of the process models, what are the benefits and drawbacks of using the model?(8) When code components are generated automatically by a tool or reused from a repository, how should coding, documentation, and design standards be enforced?(9) Many organizations buy commercial software, thinking it is cheaper than developing and maintaining software in-house. Describe the pros and cons of using COTS software.5. Compute(1) Suppose a program contains N decision points, each of which has two branches. How many test cases are needed to perform path testing on such a program? If there are M choices at each decision point, how many test cases are needed for path testing? Can the programs structure reduce this number? Given an example to support your answer.(2) Following figure is an activity graph for a software development project. The number corresponding to each edge of the graph indicates the number of days required to complete the activity represented by that branch. For example, it will take 4 days to complete the activity that ends in milestone E. for each activity, list its precursors, and compute the earliest start time, the latest start time, and the slack. Then, identify the critical path.(3) Let P be a program component that reads a list of N records and a range condition on the record key. The first seven characters of the record form the record key. P reads the key and produces an output file that contains only those records whose key falls in the prescribed range. For example, if the range is “JONES” to “SMITH”, then the output file consists of all records whose keys are lexicographically between “JONES” and “SMITH”. Write the input and output conditions as assertions to be used in proving P correct. Write a flow diagram of what Ps logical flow might be and identify the transformation points.(4) A large government agency wants to contract with a software development firm for a project involving 20,000 lines of code. The Hardand Software Company uses Walston and Felixs estimating technique for determining the number of people required for the time needed to write that much code. How many person-months does Hardand estimate will be needed? If the governments estimate of size is 10% too low (i.e., 20,000 lines of code represent only 90% of the actual size), how many additional person-months will be needed? In general, if the governments size estimates is k% too low, by how much must the person-month estimate change?(5) Suppose a mathematicians calculator has a function that computes the slope and intercept of an equation of a line. The requirement in the definition document reads: “The calculator shall accept as input an equation of the form Ax+By+C=0 and print out the slope and intercept.” The system implementation of this requirement is the function LINE whose syntax is LINE(A,B,C), where A and B are the coefficients of x and y, and C is the constant in the equation. The result is a printout of D and E, where D is the slope and E the intercept. Write this requirement as a set of causes and effects, and draw the corresponding cause-and-effect graph.(6) Following figure illustrates the component hierarchy in a software system. Describe the sequence of tests for integrating the components using a bottom-up approach, a top-down approach, a big-bang approach, and a sandwich approach.6. Practise and analyze(1) Write a set of UML models (use-case diagram, MSC diagrams, class diagram) for an online telephone directory to replace the phonebook that is provided to you by your phone company. The directory should be able to provide phone numbers when presented with a name; it should also list area codes for different parts of the country and generate emergency telephone numbers for your area.(2) Draw data-flow diagrams to illustrate the functions and data flow for the on-line telephone directory system specified in the previous problem.(3) Design a simple interpreter. Your system will accept a string of characters and determine if it is a valid command in the language. Write an error message if it is not valid, and execute the command if it is. How does your design handle faults? Discuss the pros and cons of different fault detection, prevention, and tolerance strategies for your design.(4) Manny, the Royal Service Station manager, is going to expand his services to include car washing. It is to be an automated system. The customer chooses the type of wash and notes the type of car. The system computes the fee and displays the amount due on a control panel. The customer can then pay for the car wash. After payment, if the wash is currently busy, the system indicates that the customer must wait. Otherwise, the system indicates that the customer should drive the car into the car wash bay. Using the description develop a set of use cases for a car wash.(5) You are asked to write a program to print out a yearly calendar. The user enters the year desired, and the output is a calendar for that year. D