EEE125程序设计辅导、写作C/C++课程

” EEE125程序设计辅导、写作C/C++课程EEE125 – C programming program writing assignment 20/21 1 ( University of Sheffield 98-20)EEE125 Programming in C Course: program writing assignmentAt the first lecture, you were introduced to the make-up of this course and explained that the course would beassessed by means of a Multiple Choice Question Blackboard test (worth 33.3% of the available marks) andthis C assignment task (also worth 33.3%). In semester 2, you will have a final test which covers bothMatlab and more advanced C programming writing exercises (this covers the remaining 33.4% of the marks).For this assessed assignment you are asked to write a program in C to carry out the particular taskdetailed here.1 Administrative detailsYour program must be handed in via Blackboard. The hand-in date for this exercise is 4.59pm on Tuesday15th December. You can hand your work in anytime between the beginning of week 10 and the deadlinedate. You are very strongly urged to not leave your submission to the latest possible moment to avoidcomputer related submission errors. Late submission will result in a deduction of 5% of the total mark awarded for each working day after thesubmission Date, this is Faculty policy. (Working days Monday to Friday – include working days withinstandard vacation times). The only exceptions to this will usually be where illness or other serious extenuatingcircumstances have meant missing the hand-in date (medical evidence will often be needed to sustain thisexception). In Such circumstances you MUST submit an Extenuating Circumstances form (not a selfcertificationform), available from www.sheffield.ac.uk/ssid/forms/circs, (before completing such a formmake sure you read the Explanatory notes here first: https://www.sheffield.ac.uk/ssid/forms/circsnotes) handthe form in to the department Student Support Office (Suite 27, level 1, 3 Solly Street building) or emaildirectly to Matthew Hobbs. If you believe you have good reason to ask for an extension to this hand-in date, you may discuss thecircumstances with Matthew Hobbs and, at his discretion, a later hand-in date may be negotiated. (But pleasedo the discussing well in advance of the Original hand-in date expiring). Please note: being disorganised orlazy and so failing to meet the hand-in date by simply leaving tackling the exercise until its too late is nota good reason and will not normally result in an extension of the hand-in date!________________________________________________________________________________________2 What your program should doElsewhere in your studies you may have heard of the Least Squares method often used to generate a best fit straightline through a set of data plotted on a graph (where a straight line relationship is expected to exist). The Least Squaresmethod is very useful when working with data derived from experiments and indeed it may well be a technique of use toyou elsewhere in course work.The aim of this assessed exercise is: for you to write a program in C that uses the least squares technique to allow a userto input a set of data value and to compute and output as results the gradient (m) and offset (c) of the best fit straightline through that entered set of data. You do not need to understand the underlying mathematics (though it would help)instead all you need to do is Correctly implement the formulae given in this assignment sheet.2.1 The Least Squares formulae neededConsider you have a set of data comprising pairs of measurements of two related variables: x y. You believethe relationship between these variables can be expressed as a straight line, using the standard straight lineequation (where y is the dependent variable and x is the independent variable, m is the gradient of the line – thatis the rate of change of y with respect to x – and c is the intercept (or offset) of the line with the y axis that isthe value of y when x is zero). Here is the standard straight line equation:y = m. x + cEEE125 – C programming program writing assignment 20/21 2 ( University of Sheffield 98-20)Look at the example graph Shown below. Pairs of x, y data have been plotted (the little + marks) and a best fitstraight line drawn through them (the dotted line). The gradient of the best fit straight line is m and theintercept (offset) of that line with the y axis from the origin of the graph is c.From theory we can obtain the equations needed todraw a best fit straight line Through such a set of datausing Least Squares as our technique.Consider we have a set of data samples where values ofy have been measured for a range of different valuesof x. Consider we have taken N samples (i.e. pairsof x and y data of the form: [x1 y1] [x2 y2] [x3 y3] [xNyN]). Then using this notation we can write thefollowing equations:The least squares equation for the gradient of the best fit line m is:The least squares equation for the offset of the best fit line c is:When interpreting these formulae you might like to be reminded that:Although these formulae May initially look daunting, note that they contain some common terms,appears in the formulas above. By identifying such common terms you can perhapssave effort by calculating them only once and use the results when those terms appear in later equations or writingone function to do this and use it each time its needed.EEE125 – C programming program writing assignment 20/21 3 ( University of Sheffield 98-20)2.2 How the program should appear to the user the Requirements.Reminder, the aim of this assessed exercise is for you to write a program that will allow the user to enter a setof data (in the form of x, y pairs) and then uses the least squares technique to calculate and display the gradient(m) and offset (c) of the best fit straight line through that set of data.a) The program should begin by briefly announcing its purpose to the user.b) Next it should ask the user how many pairs of data values (sets of x and y) they intend to input, onlypermitting the user to choose numbers of pairs in the range from 4 to 20 pairs (that is the user should bepermitted to enter no fewer than 4 pairs and no more than 20 pairs).c) Make sure your program displays clear instructions to the user at each stage so that the user knows exactlywhat the program wants them to do.d) The program Should then ask the user to input the specified number of data value pairs, storing them in suitablevariable(s). Your program should be able to accept values for x and y entered as real numbers. Your programshould accept only positive numbers that are in the range between l000000.0 and 0.000005.e) Next the program should neatly display all the data pairs entered in a tidy way on the screen.f) The program should use the least squares formulae described section 2.1 above to process the set of dataentered and so calculate the values for m and c for the best fit straight line through that set of data.g) The program should then neatly display the values of m and c that it has calculated.h) The program should then ask the user if they would like to repeat the program, interpret their reply, and, iftheir answer is yes then the program should repeat again all steps from step b) onwards.Please note: When designing you program: be careful to ensure that it makes efficient use of variable space by choosingsuitable types for your variables that do not waste memory unnecessarily. Dont just assume this programwill be compiled to run on a PC with the Dev-C compiler, make sure you use the smallest C type variablesnecessary according to the minimum sizes given for the standard C types in the lectures. Also makeappropriate use of the various flow-control statements C has to offer to build loops where they would behelpful. You should divide your Program up into separate functions. Programs that consist of everything inside thesingle function main only will earn far fewer marks than programs that are divided into more than onefunction.2.3 A sample data set to use for testingHere is some sample data upon which you might like to test your program:First a simple set (you could try plotting it as a graph and estimating m and c by hand):The results are: Gradient of best fit straight line m = 1.025 approx. with and a y intercept at c = 1.911 approx.EEE125 – C programming program writing assignment 20/21 4 ( University of Sheffield 98-20)Now a more complex set:The results are: Gradient of best fit straight line m = 0.0634 and a y intercept c at -2.907.2.4 Some helpful hints Your program must be written in C and not C++. (C is taught in EEE125, not C++, so sticking totechniques you have been taught will mean you will be OK). Make sure you save your file with a .cfilename extension NOT .cpp. When using Dev-C, make sure when saving your file that the SaveFile dialogue has the Save as type drop-down menu set for C source files (*.c). By the time this sheet is handed out you will have already covered, in lectures and lab sheets, all thematerial necessary to allow you to write a suitable program. However, future lectures and backgroundreading of your own may be of additional help. Make your program code as easy to read (by a human) as possible. For example partition it (in other wordsbreak it up) by making your own functions. (Programs that consist of everything inside the single functionmain only will earn fewer Marks than programs that are divided into more than one function). (See examplesolution to Lab 6 question 4 file TUT6Q4-4.c in the EEE125 MOLE course, in the Lab Classes section, inthe Lab Class Downloads folder and finally in the Lab Sheet 6 Downloads showing use of functions).Use well-chosen identifiers for function names and variable names so that the purpose of a particularfunction or variable is hinted by its name. This example solution will be made available during week 8 ofthe semester. Make sure the program is well commented (i.e. using /* */ marks) so that the purpose of each part is clear.These comments should be concise. Note: there is no need to use comments to explain how a particular Cconstruct works, you can assume the reader understands the C language itself (e.g. you dont need to explainhow a for loop works as such). However you should add comments to explain what your program aims toachieve with particular C constructs where it isnt immediately obvious (e.g. explain what useful task aparticular for loop is performing for you in your particular program). This is an important skill needed byprogrammers to ensure their program code is readable and understandable by others who may have causeto examine it or modify it later. You have been given clear guidance in the lectures about how to lay out aprogram and how to add comments check your lecture slides to see what was said. Dont forget: planning your program thoroughly on paper first is by far the most effective way of quicklywriting a good program. Dont rush to coding at the PC too soon. Start by breaking the task down intomanageable portions, then plan the sequence of events for each portion with flow-charts and pseudo code etc.Flow-charts in particular will help you identify the appropriate flow control statements (while, do..while,for, if etc.) to choose. Test the output from your Program by using various sets of data. You can generate your own test data quiteeasily. Use a calculator or a spreadsheet to help verify your results. Dont forget to check your programsbehaviour with illegal data (i.e. data outside the range allowed for input), does it behave appropriately?EEE125 – C programming program writing assignment 20/21 5 ( University of Sheffield 98-20) Dont forget, divide and conquer is a wise approach. Break the task down into manageable portions andtackle them one at a time, dont try and code up the whole program in one go only to find it doesnt work. Thetask of finding a fault (or more likely many faults) in a large program is like looking for a needle in a haystack- make sure you have only a small haystack to search! Start off with a small program which only does thefirst few steps of the task, Get that working first. Next add a bit more to your program and get that workingtoo. Continue in this way until the program can carry out the complete task Above all, be sure to hand something in by the hand-in date. If you examine the marking scheme carefully(see later) you will see that only a small proportion of the marks are available for accuracy of results, etc.There are many more marks available for other aspects of the work. If you only manage to produce aprogram that asks for, stores and re-displays the input sample data values but does not even attempt to doanything else then you can at least be given some marks for that much (which is better than no marks if youhand in nothing!) If you need help:a) Please talk to your demonstrators during a timetabled online Tuesday afternoon computer lab. session, ora timetabled face-to-face Wednesday morning computer lab. session.b) Be sure to make full use of the C books in the library and the web links provided in our Blackboardcourse as well as other available online resources.3 What should you hand in?3.1 The program itself: You should hand your C program file itself in via Blackboard (see instructions in section 3.2 below)and it should be in the form of a source file of C code (that is the ASCII text file created in the usual way byusing the Dev-C++ Editor when writing a program and saved with the filename and the file name extensionfor C Source Files: leastsq.c). You MUST name the file leastsq.c Please use this name only, ithelps with processing your Work quickly. It must not be called leastsq.cpp! (*.cpp implies a C++file and you must not write in C++!). Use of an incorrect filename will result in lost marks. You MUST write your Registration number into a comment string as the first line of your program likethis:/* My Reg Number: 180113134 */#include stdio.hand so on. You are NOT required to include your name. If, for any reason, you choose to write and test your program using a `C compiler other than the BloodshedDev-C environment provided for you on the Universitys Computer network (as used in the lab.sessions), then you are strongly recommended to test the final version of your source code within the DevCcompiler environment on the Universitys Computer network and check that it compiles and runs correctlybefore handing it in. It is this same Dev-C compiler environment that will used to compile and test yourprogram in order to assess it! If you have used a different compiler, and your program does not compileon the Dev-C compiler environment, you will lose marks.EEE125 – C programming program writing assignment 20/21 6 ( University of Sheffield 98-20)3.2 Submitting your file:To submit your program via Blackboard, follow these instructions (follow them carefully as you only get onechance to submit!):a) You only have one chance to submit your file, once submitted you cannot change it, so be sure you arefinished and have chosen the correct file to submit and attach it correctly.b) Once you have Finished your C source file and you are happy that it is ready to submit, open a webbrowser and either login in to Blackboard via MUSE.c) On the EEE125 Programming course home page look for the Assessment and Feedback section inthe left-hand menu.d) In the Assessment and Feedback section of this left-hand menu you should see a heading calledAssessment. Click on this.e) You should now see an item titled C Programming Course, Assessed Exercise No. 1, make sure youclick on this title.f) Scroll down to section Assignment Submission. DO NOT use the Create Submission button. Lookbelow and you will see a line beginning Attach file and a button marked Browse My Computer.Click on this. A file browser window should now open.g) In the file browser window navigate to your folder and select your C source file leastsq.c in theconventional way. (Make absolutely sure you are selecting the C source file – the one you typed notany of the other associated files the compiler generates when you compile and run your program). To dothis, look at the icon displayed beside the file name, make sure you pick the file with the icon showing asmall blue .c in the corner. Double click on your leastsq.c file to attach it. It should now appear ina list of Attached files.h) Once you are sure you have attached your leastsq.c file then scroll to the bottom of the page and youshould see the Submit button on the right hand side, click this button to submit your work. Note: Youmust NOT write anything in the Add Comments box (anything this placed here will not be read).EEE125 – C programming program writing assignment 20/21 7 ( University of Sheffield 98-20)3.3 Marking SchemeHere is the marking scheme that will be used to mark your work. Initially, as you can see, you will be markedout of 100, full marks would be 100%.Does the program try to meet the specification laid out in thissheet? Is it designed to do all the things asked for?Have variables been created using appropriate types and do theymake efficient use of storage space?Have the many useful C language features discussed inlectures and tutorials been exploited? Are the C constructsused appropriately?Is the programs purpose easily understood from the way itsstructured e.g. does it Have an appropriate hierarchical form(exploiting functions?). Is it well (concisely and clearly)commented? Have sensible, self explanatory, identifiers beenchosen for function names and variable names?Have user functions other than main been written at all? Arethey used sensibly? Is the choice of return types and parameterssensible?Does the program compile without errors or serious warnings?Does it run without crashing etc?Are the results it produces correct? 20User interface Does the user interface clearly inform the user what she or hemust do at each stage? Are the outputs presented clearly and inan appropriate fashion?The basic principle underlying assessed work is that the work submitted for assessment must be entirelyyour own. No one objects to you discussing the principles of C programming in general with others, but:plagiarism and collusion are not allowed. You must not discuss the details of how to do this exercise with anyone other than Matthew Hobbs or one of the lab. demonstrators (GTAs). In the context of this exercise, unfairmeans would include:1 You MUST NOT allow anyone else to write or dictate to you your program, in whole or in part.2 You MUST NOT look at someone elses program for this exercise or copy from someone elses work orexchange emails or internet chat messages (MSM, Weibo, Whatsapp, Facebook, Google Meet,Blackboard or similar) with someone else which include code from either your program or their programfor this exercise. Note: this includes with the lab. Demonstrators or students in other years.3 Likewise you MUST NOT write program code for, or share program code with, another student on thiscourse or from previous years of study or anyone else.4 You MUST NOT team up with others to write one program (in whole or in part) together, then all hand inprograms containing that Same code (in whole or in part).5 You MUST NOT copy portions of code from any sources (that are not of your own creation) such as awebsite or a book or from someone elses computer, website (even from a website where the language is notEnglish) or memory device. (However: you are granted exceptional permission to copy from any of theEEE125 – C programming program writing assignment 20/21 8 ( University of Sheffield 98-20)examples of code that have been given to you during this course as lecture or tutorial examples if youdo this, then attribute the source of those portions of code by clearly referencing it using a comment likethis /* taken from EEE125 examples */ immediately before and immediately after the codeconcerned.)Remember: the basic principle underlying assessed work such as this is that the work submitted forassessment must be entirely your own. We wish to only give marks for programs written by you alone!If you are in any doubt about what might constitute unfair means in the context of this exercise then pleasediscuss any areas of uncertainty with Matthew Hobbs. If you experience any problems with this assignmentthen seek help from Matthew Hobbs or the demonstrators present during lab. sessions.Please note: We will be using a sophisticated program specially designed to detect plagiarism in a set of Cprograms to help detect evidence of Such unfair means in the assessed work that you hand in, so, please donttake the risk of copying work, submit only work done by you entirely on you own. Where we suspect unfairmeans to have been used, the department reserves the right to give zero marks to all individuals concernedand/or refer you to the University Discipline Committee and/or place a note in your student record file(We have caught people breaking these recommendations before and done all these things, so do please note thewarning!).如有需要，请加QQ：99515681 或邮箱：99515681@qq.com

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