QuestionAnswered step-by-stepFor each of the following claims, state whether it is true or not…For each of the following claims, state whether it is true or not and give a briefjustification.(i) For any linear program with n variables and m constraints, there are atdifferent basic solutions. [2 marks](ii) The Simplex Algorithm has a worst-case polynomial runtime. [2 marks](iii) In each iteration of the Simplex Algorithm, the value of the objectivefunction changes. [2 marks](iv) The auxiliary linear program in Initialize-Simplex always has a feasiblesolution. [2 marks](v) The fundamental theorem of linear programming also holds if linearconstraints are allowed to be strict. [2 marks](vi) The set of feasible solutions of any linear program forms a convex set.[2 marks](b) For the following linear program, write down the auxiliary linear program usedby Initialize-Simplex in slack form: [3 marks]minimize ? 4×1 + x2subject to ? 4×1 + 2×2 ? ?4×1 ? 6×2 ? ?3(c) Recall the algorithm for the unweighted vertex cover problem that is based onrounding the solution of a linear program.(i) What is the approximation ratio of this algorithm? [1 mark](ii) Give an example of a graph and the corresponding linear program for whichthe gap between the linear program solution and optimal solution is as largeas possible. [4 marksWhat is the approximation ratio of an approximation algorithm? [2 marks] (ii) State the definitions of PTAS and FPTAS. [4 marks] (b) Consider the two approximation algorithms for VERTEX-COVER from the lectures (one greedy algorithm and one based on rounding a linear program). (i) What are the approximation ratios of these two algorithms? [2 marks] (ii) Construct an input graph that demonstrates the tightness of the approximation ratio of the greedy algorithm (for full marks, your construction should work for any even number of vertices n). [3 marks] (c) Consider the following randomised algorithm to compute a solution of the VERTEX-COVER problem for an unweighted graph G = (V, E): Let C be the empty set While E not empty do Pick any edge e={u,v} from E Choose x from {u,v} uniformly at random Add x to C Remove all edges incident to x from E End While Return C (i) Explain briefly why the set C returned is a valid vertex cover. [2 marks] (ii) Find a lower bound on the probability that the algorithms returns an optimal solution. Hint: For each edge e = {u, v} picked by the algorithm consider the event that the chosen vertex x ? {u, v} added to C is also part of an optimal cover. [4 marks] (iii) Given a lower bound p ? (0, 1) on the probability that this algorithm returns an optimal solution, describe a new algorithm that returns an optimal solution with probability at least ?, for any given ? ? [p, 1). [3 marks) A programmer directly implements this formula when writing a function to multiply two matrices. Find the asymptotic time complexity of such an algorithm, taking care to justify your answer. [3 marks] (b) An alternative strategy to compute Z is to divide A and B into four n 2 × n 2 matrices. Computing Z then involves eight n 2 × n 2 matrix multiplications followed by a series of matrix additions. This approach is then applied recursively. (i) Identify the algorithmic strategy in use. [1 mark] (ii) Show that the run time of this alternative strategy is given by the recurrence relation tn = Ktdf(n)e + O(g(n)) where tn is the time to compute the product of two n × n matrices, K is a constant you should determine, and f(n) and g(n) are functions that you should identify. [6 marks] (iii) Solve the recurrence relation to find an asymptotic complexity for tn. [5 marks] (c) An optimisation of the algorithm presented in part (b) means that only seven matrix multiplications are needed rather than the eight previously suggested. State the new recurrence relation and solve it to show that this algorithm is O(ow does the assumption of temporal locality of reference influence page replacement decisions? Illustrate your answer by briefly describing an appropriate page replacement algorithm or algorithms. [3 marks] (iv) What is meant by spatial locality of reference? [2 marks] (v) In what ways does the assumption of spatial locality of reference influence the design of the virtual memory system? [3 marks] (b) Buses are used to connect devices to the processor. (i) Describe with the aid of a diagram the operation of a synchronous bus. [4 marks] (ii) In what ways does an asynchronous bus differ? [2 marksConsider an operating system that uses hardware support for paging to provide virtual memory to applications. (a) (i) Explain how the hardware and operating system support for paging combine to prevent one process from accessing another’s memory. [3 marks] (ii) Explain how space and time overheads arise from use of paging, and how the Translation Lookaside Buffer (TLB) mitigates the time overheads. [3 marks] (b) Consider a system with a five level page table where each level in the page table is indexed by 9 bits and pages are 4 kB in size. A TLB is provided that is indexed by the first 57 bits of the address provided by the process, and achieves a 90% hit rate. A main memory access takes 40 ns while an access to the TLB takes 10 ns. The maximum memory read bandwidth is 100 GB/s. (i) What is the effective memory access latency? [4 marks] (ii) A colleague suggests replacing the system above with one that provides 80 GB/s memory read bandwidth and main memory access latency of 30 ns. Explain whether you should accept the replacement or not, and why. [4 marks] (c) A creative engineer suggests structuring the TLB so that not all the bits of the presented address need match to result in a hit. Suggest how this might be achieved, and what might be the costs and benefits of doing so. [6 marks] (a) Describe two quantitative and two qualitative techniques for analysing the usability of a software product. [4 marks] (b) Compare the costs and benefits of the quantitative techniques. [6 marks] (c) Compare the costs and benefits of the qualitative techniques. [6 marks] (d) If restricted to a single one of these techniques when designing a new online banking system, which would you choose and why?(a) Suppose that women who live beyond the age of 80 outnumber men in the same age group by three to one. How much information, in bits, is gained by learning that a person who lives beyond 80 is male? [2 marks] (b) Consider n discrete random variables, named X1, X2, . . . , Xn, of which Xi has entropy H(Xi), the largest being H(XL). What is the upper bound on the joint entropy H(X1, X2, . . . , Xn) of all these random variables, and under what condition will this upper bound be reached? What is the lower bound on the joint entropy H(X1, X2, . . . , Xn)? [3 marks] (c) If discrete symbols from an alphabet S having entropy H(S) are encoded into blocks of length n symbols, we derive a new alphabet of symbol blocks S n . If the occurrence of symbols is independent, then what is the entropy H(S n ) of this new alphabet of symbol blocks? [2 marks] (d) Consider an asymmetric communication channel whose input source is the binary alphabet X = {0, 1} with probabilities {0.5, 0.5} and whose outputs Y are also this binary alphabet {0, 1}, but with asymmetric error probabilities. Thus an input 0 is flipped with probability ?, but an input 1 is flipped with probability ?, giving this channel matrix p (i) Give the probabilities of both outputs, p(Y = 0) and p(Y = 1). [2 marks] (ii) Give all the values of (?, ?) that would maximise the capacity of this channel, and state what that capacity then would be. [3 marks] (iii) Give all the values of (?, ?) that would minimise the capacity of this channel, and state what that capacity then would be. [3 marks] (e) In order for a variable length code having N codewords with bit lengths 1 mark] (f ) The information in continuous signals which are strictly bandlimited (lowpass or bandpass) is quantised, in that such continuous signals can be completely represented by a finite set of discrete samples. Describe two theorems about how discrete samples suffice for exact reconstruction of continuous bandlimited signals, even at all the points between the sampled values. [4 mark(a) A two state Markov process emitsthe letters {A, B, C, D, E} with theprobabilities shown for each state.Changes of state can occur whensome of the symbols are generated,as indicated by the arrows.4.2 Information sources with memoryWe will wish to consider sources with memory, so we also consider Markovprocesses. Our four event process (a symbol is generated on each edge) isshown graphically together with a two state Markov process for the alphabetfA, B, C, D, Eg in gure 17. We can then solve for the state occupancy usingow equations (this example is trivial).ess with states fS 1; S2; : : :Sng,with transition probabilities pi(j) being the probability of moving from state Sito state Sj (with the emission of some symbol). First we can dene the entropy where C repeatwhile E has the same meaning as do C while E in C or Java.(a) List the terminals and non-terminals of this grammar and explain thesignifificance of S. [3 marks](b) Identify any ambiguities in the above grammar and rewrite it to remove them,ensuring that your new grammar generates exactly the same set of strings.[4 marks](c) Specify a suitable abstract syntax, for example by giving a type declarationin a programming language of your choice, which might be used to hold parsetrees for this language. [3 marks](d) Give either a recursive descent parser or a characteristic fifinite state machine(e.g. for SLR(1)) with associated parser for your grammar. Your parser neednot return a parse treeit suffiffiffices for your parser either to accept or to rejectthe input string. [10 marks]4CST.2001.4.55 Data Structures and Algorithms(a) Outline how you would determine whether the next line segment turns left orright during the Graham scan phase of the standard method of computing theconvex hull of a set of points in a plane. [5 marks](b) Describe in detail an effiffifficient algorithm to determine how often the substringABRACADABRA occurs in a vector of 106 characters. Your algorithm should beas effiffifficient as possible. [10 marks](c) Roughly estimate how many character comparisons would be made when youralgorithm for part (b) is applied to a vector containing 106 characters uniformlydistributed from the 26 letters A to Z. [5 marks]6 ECAD(a) When designing clocked circuits there are times when asynchronous inputshave to be sampled which may result in metastable behaviour in state holdingelements. How might metastability be avoided when sampling asynchronousinputs? [5 marks](b) An optical shaft encoder (e.g. used on the internal rollers of a mechanicalmouse) consists of a disk with an evenly spaced alternating transparent andopaque grating around the circumference. Two optical sensors are positionedsuch that when one sensor is at the middle of an opaque region, the otheris at the edge. Consequently, the following Gray code sequence is produced,depending upon the direction of rotation:positive rotationnegative rotation A shaft decoder module is required to convert the Gray code into an 8-bitposition. The 8-bit position should be incremented every time the inputchanges from one state to another in a positive direction (e.g. from 00 to01, or from 10 to 00). Similarly, the 8-bit position should be decrementedevery time the input changes from one state to another in a negative direction(e.g. from 00 to 10, or from 01 to 00).Write and comment a Verilog module which performs the function of a shaftdecoder. [15 marks]5[TURN OVERCST.2001.4.67 Operating System Functions(a) In the context of virtual memory management:(i) What is demand paging? How is it implemented? [4 marks](ii) What is meant by temporal locality of reference? [2 marks](iii) How does the assumption of temporal locality of reference inflfluence pagereplacement decisions? Illustrate your answer by brieflfly describing anappropriate page replacement algorithm or algorithms. [3 marks](iv) What is meant by spatial locality of reference? [2 marks](v) In what ways does the assumption of spatial locality of reference inflfluencethe design of the virtual memory system? [3 marks](b) A student suggests that the virtual memory system should really deal with”objects” or “procedures” rather than with pages. Make arguments both forand against this suggestion. [4 and 2 marks respectively]. (c) Describe an O(n) algorithm to discover all the strongly connected componentsof a given directed graph and explain why it is correct. You may fifind it usefulto use the concept of the forefather ?(v) of a vertex v which is the vertex, u,with highest fifinishing time for which there exists a (possibly zero length) pathfrom v to u. [10 marks]2 Computer Design(a) What is a data cache and what properties of data access does it exploit?[5 marks](b) What is a direct mapped cache and under what conditions will it exhibit poorperformance? [5 marks](c) Under what circumstances might a word of data in main memory besimultaneously held in two separate fifirst-level cache lines? [5 marks](d) A translation look aside buffffer is a specialised cache. What does it typicallystore and why is it often a factor of 1000 smaller than a data cache? [5 marks]2CST.2001.6.33 Digital Communication I(a) Defifine the terms circuit and packet in the context of communication systems.[5 marks](b) What sort of guarantee does circuit switching provide? [5 marks](c) What advantages does packet switching provide over circuit switching?[5 marks](d) Which of frequency division multiplexing, time division multiplexing and codedivision multiplexing lend themselves to circuit switching? Which to packetswitching? Explain why or why not in each case. [5 marks]4 Computer Graphics and Image Processing(a) Describe the z-buffffer polygon scan conversion algorithm. [10 marks](b) In ray tracing, once we have determined where a ray strikes an object, theillumination at the intersection point can be calculated using the formula:I = Iaka +XiIikd(Li · N) +XiIiks(Ri · V)nExplain what real effffect each of the three terms is trying to model and explainwhat each of the following symbols means, within the context of this formula:I, Ia, i, Ii , ka, kd, ks,Li, N, Ri, V, n[10 marks]3[TURN OVERCST.2001.6.4SECTION B5 Comparative Programming Languages(a) Brieflfly explain the concept of coroutines as used in BCPL and outlinethe effffect of the library functions createco(f, size), deleteco(ctpr),callco(cptr, val) and cowait(val). [10 marks](b) Outline how you would design a coroutine to merge, in increasing order, twoinfifinite streams of increasing integers supplied by two other coroutines.[5 marks](c) Brieflfly outline how you would implement an analogous merging mechanism inan object-oriented language, such as Java, that does not provide a coroutinemechanism. [5 marks]6 Compiler Construction(a) Describe one possible structure (e.g. ELF) of an object fifile. Illustrate youranswer by considering the form of object fifile which might result from thefollowing C program.int a = 1, b = -1;extern int g(int);extern int c;int f() { return g(a-b) + c; }It is not necessary to consider the exact instruction sequence, just issuesconcerning its interaction with the object fifile format. [10 marks](b) Describe how a linker takes a sequence of such programs and produces anexecutable fifile. [4 marks](c) Compare and contrast static and dynamic linking in a system using your objectfifile format. [6 marks]4CST.2001.6.57 Prolog for Artifificial IntelligenceA weighted binary tree can be defifined using compound terms in the following way.A node of the tree is represented by the term n(V, L, R), where V stands for thevalue of the node, and L and R stand for the left and right branches, respectively.A terminal node has the R and L components instantiated to the null list.Given an input tree T, write a Prolog program that constructs a tree of the sameshape as T, but in which the value of each node has been set to the value of themaximum value node in T.[Note: Maximum marks are available only for programs that perform this task inone recursive descent of the input tree, and which use no more than four clauses.][20 marks]5[TURN OVERCST.2001.6.68 DatabasesThe environmental agency is setting up an SQL database to monitor long-termtrends in the climate. Data are collected from observatories of a number of difffferentkinds.Flood risk is of particular concern. Each water authority measures river levels andrates of flflow hourly at major points, and records reservoir levels daily.In addition, the agency maintains weather stations both inland and at sea. Theserecord precipitation (rainfall etc.), temperature, sunshine, air pressure and wind.Values of new precipitation, temperature, pressure, and wind speed and directionare taken hourly; gusts of over 60 m.p.h. are noted whenever they occur.Maximum and minimum temperature and pressure, the total number of hours ofsunshine and the total precipitation are recorded daily. Inland stations can begrouped by water authority.By default these primary data will be relegated to archive after 2 years. Selectedinformation is retained permanently in a data warehouse. This serves two purposes.First, it holds monthly summary data consisting of the maximum (and minimumas appropriate) day value for each statistic, together with the monthly totals ofsunshine and precipitation. The warehouse also keeps detailed information relatingto periods of extreme weather from the relevant observatories, with one or morekeywords describing the nature of the incident (flflood, blizzard, hurricane etc.) andan optional comment.Write notes to assist in the design of the schema for the relational data warehouse,including any diagrams that you fifind helpful. Explain how your design will enablemeteorologists to fifind relevant past records, noting any assumptions that you makeabout the nature of the data.[You should not go into unnecessary detail about the structure of the primarydatabase. You may assume that expert meteorologists will select the data for thewarehouse.][20 marks]6CST.2001.6.7SECTION C9 Semantics of Programming LanguagesWrite short notes on four of the following fifive topics.(a) The relationship between three forms of operational semantics of the Languageof Commands (LC) given by an evaluation relation h P, si ? hV, s0 i a transition relation h P, si ? hP0 , s0 i a transition relation between the confifigurationsh c, r, si of theSMC-machine(b) The notion of semantic equivalence of LC phrases and its congruence property.(c) Call-by-name and call-by-value rules for evaluating function applications in theLanguage of Functions and Procedures (LFP) and the relationship between theevaluation relations for LFP based upon each of them.(d) The notion of bisimilarity of two confifigurations in a labelled transition system.(e) The rules defifining the possible labelled transitions of parallel composition(P1|P2) and restriction (? c . P) in the Language of Communicating Processes(LCP).[5 marks each]7[TURN OVERCST.2001.6.810 Foundations of Functional ProgrammingThe following are some concepts that have flflourished in the context of functionalprogramming but which have (so far) been less heavily used in main-streamlanguages even when they have been available:(a) polymorphic types(b) type reconstruction(c) higher-order functions(d) lazy evaluation(e) continuationsFor each case give a brief explanation of the facility referred to, suggest acircumstance in which it might be useful and comment on how immediately relevantto non-functional languages it seems.[4 marks per part]8CST.2001.6.911 Logic and Proof(a) In the context of clause-based proof methods, defifine the notion of pure literaland describe what should be done if the set of clauses contains pure literals.[3 marks](b) Use the Davis-Putnam method to discover whether the following set of clausesis satisfifiable. If they are satisfifiable, show a satisfying interpretation.{P, R} {¬P, ¬R} {P, ¬Q} {¬Q, R} {¬P, Q, R}[6 marks](c) The three-fifingered inhabitants of the planet Triterra build base-3 computers.A Triterran named Randal Tryant has found a way of verifying base-3combinational logic. His Ordered Ternary Decision Diagrams (OTDDs) arethe same as a technology used on planet Earth except that all variables andexpressions range over the values 0, 1 and 2 instead of just 0 and 1.(i) Describe how a full ternary decision tree can be reduced to an OTDDwithout regard for effiffifficiency. [2 marks](ii) Sketch an effiffifficient algorithm to convert a ternary expression directly to anOTDD without constructing the full decision tree. For a typical ternaryconnective use modulo-3 multiplication, written as ?. [6 marks](iii) Demonstrate your algorithm by applying it to the ternary expression((i ? i) ? j) ? 2. [3 marks]9[TURN OVERCST.2001.6.1012 Complexity Theory(a) Show that any language that can be accepted by a nondeterministic machinein time f(n) can also be decided by a deterministic machine in space O(f(n)).[4 marks](b) Show that any language that can be accepted by a nondeterministic machinein space f(n) can also be decided by a deterministic machine in timeO(c(f(n)+log n) ), for some constant c. [6 marks](c) Explain what the above results tell us about the inclusion relationships amongthe complexity classes:NL, co-NL, P, NP, PSPACE and NPSPACE[4 marks](d) It has been proved that the graph reachability problem is in co-NL. Whatfurther inclusions can you derive among the above complexity classes usingthis fact? Explain your answer. [6 marks]Describe an O(n log(n)) algorithm based on a variation of merge sort to fifind theclosest pair of a given set of points lying in a plane. You may assume that the setof points is given as a linked list of (x, y) coordinates. [8 marks]Carefully prove that your algorithm can never take longer than O(n log(n)).[6 marks]Modify, with explanation, your algorithm to fifind the pair of points with minimumManhattan distance. The Manhattan distance between points (x1, y1) and (x2, y2)is |x1 ? x2| + |y1 ? y2|. [6 marks]1[TURN OVERCST.2000.6.22 Computer DesignWhy are the following statements fallacies?(a) MIPS is an accurate measure for comparing performance among computers.[5 marks](b) A benchmark is a typical program which accurately predicts the performanceof all other applications. [5 marks](c) Complex instruction set computers minimise the semantic gap betweenmachine code and high-level languages, thereby making applications run morequickly. [5 marks](d) Data caches always improve processor throughput. [5 marks]3 Digital Communication ICompare circuit switching and packet switching, paying attention to channelcharacteristics and resource effiffifficiency. [7 marks]What is wave division multiplexing (WDM)? Is it more like circuit switching orpacket switching and why? [7 marks]Wave length conversion is the process, either optical or optical-electronic-optical,of receiving a signal on one wavelength and transmitting on another.How does wave length conversion ease the problem of routing optical carriers in anetwork? [3 marks]”The huge capacity of WDM systems will mean that IP becomes redundant.”Discuss. [3 marks]2CST.2000.6.34 Computer Graphics and Image ProcessingGive an algorithm for drawing the part of a circle which lies in the fifirst octant.Assume that the circle has integer radius and is centered at the origin. Assumethat you have a function setpixel(x, y) which turns on pixel (x, y). [10 marks]Derive a matrix, or a product of matrices, to perform a clockwise 2D rotation ofarbitrary angle, ?, about an arbitrary point, (xc, yc). [4 marks]Provide an algorithm to ascertain whether the Bezier curve defifined by P1P2P3P4lies within some tolerance, , of the straight line segment, P1P4, which joins theBezier curve’s end points. Your algorithm must return false if the Bezier curve isoutside the tolerance; it must return true if the curve is well inside the tolerance;it may return either true or false if the curve is inside, but not well inside, thetolerance. [6 marks]SECTION B5 Comparative Programming LanguagesGive a brief summary of the main syntactic constructs found in the programminglanguage Smalltalk. Other languages often have the conditional constructsif-then-else and while. Show how these two constructs can be defifined in Smalltalk.[8 marks]Illustrate the use of Smalltalk by showing how you would defifine a method tocompute the factorial of an integer. [8 marks]Although Smalltalk was originally designed to be an interpretive language, modernimplementations are dramatically more effiffifficient. Brieflfly outline what techniquesmight have been used to make this improvement. [4 marks]3[TURN OVERCST.2000.6.46 Compiler ConstructionDescribe how a parse tree can be translated into a sequence of assembly languageinstructions based on a pattern matching graph derived from a set of tree rewritingrules where each rule has a cost and a corresponding fragment of code. Illustrateyour answer using the following rules:Ri = Kk LDI Ri,Kk Cost 2Ri = add(Ri,Kk) ADDI Ri,Kk Cost 3Ri = add(Ri,Rj) ADD Ri,Rj Cost 3Ri = add(Ri,add(Rj,Kk)) ADD Ri,Rj,Kk Cost 4applied to the following parse tree:add(K1,add(add(K2,add(K3,K4)),add(K5,K6)))[15 marks]Discuss the advantages and disadvantages of this approach to code generation.[5 marks]7 Prolog for Artifificial IntelligenceOne of the regulations of the International Rugby Board (IRB) states that for aplayer to be eligible to play for a given country, the player’s father or mother orgrandfather or grandmother must have been born in that country. Assume thatthere is a complete genealogical database consisting of Prolog clauses of the formperson(P, B, F, M), where P is a person’s name, B is the country of P’s birth, F istheir father’s name and M is their mother’s name. For example, the clauseperson(bruce, australia, rhodri, bronwyn).might appear in such a database. Further assume that names in the database areconstructed so as to refer uniquely to individuals. Write Prolog clauses defifiningthe predicate eligible such that goals of the form eligible(P,C) succeed if and only ifperson P is eligible to play for country C according to the above regulation.[10 marks]Given a list of players on a given country’s team, defifine a predicate checkteamthat will check each member of the team for eligibility according to the eligiblepredicate, and furthermore check that each player appears on the list only once.The checkteam goal will fail if any player is ineligible or if any player is listed morethan once. [10 marks]4CST.2000.6.58 DatabasesDescribe the basic architecture of the ODMG standard for Object DataManagement. [10 marks]What support is provided for transactions? What locking modes are available, andhow are they used by the database runtime systems? [4 marks]The query language OQL is recognised as a standard by the Object ManagementGroup (OMG). To what extent is it similar to SQL, and in what ways does itdiffffer? [6 marks]SECTION C9 Semantics of Programming LanguagesWhat does it mean to say that two confifigurations of a labelled transition systemare bisimilar? [3 marks]Describe a labelled transition system for a language of communicating processeswith input prefifixing (c(x). P), output prefifixing (¯ch Ei . P), an inactive process (0),choice (P + P0 ), parallel composition (P|P0 ) and channel restriction (? c . P). Youmay assume there is a relation E ? n which defifines when an integer expression Eevaluates to an integer n. [7 marks]For each of the following pairs of processes, say whether or not they are bisimilar.Justify your answer in each case.(a) ¯ch 1i .((¯ch 2i . 0) + (¯ch 3i . 0)) and (¯ch 1i . c¯h 2i . 0) + (¯ch 1i . c¯h 3i . 0) [4 marks](b) P and ? c .((c(x). 0)|(¯ch 1i . P)), where c does not occur in P[6 marks]10 Foundations of Functional ProgrammingGive as simple a set of rules as you can for transforming lambda calculus to a formwhere there are no bound variables mentioned, but where there are many instancesof the three standard combinator constants S, K and I. [6 marks]Describe tree-rewrites suitable for reducing expressions written in terms ofcombinators. [6 marks]Explain how you might deal with the issue of keeping track of the values of boundvariables if you were to interpret lambda calculus directly. [8 marks]5[TURN OVERCST.2000.6.611 Logic and ProofFor each of the given pairs of terms, give a most general unififier or indicate whynone exists. (Here x, y, z are variables while a, b are constant symbols.) [4 marks]Inis laD nas 2 classes. iwoDATTay.java and Lab1java. LäDI 1java IS alreaay given to you. Do not make any changes to this file. The only file you are expected to write for this lab is TwoDArrayjava 2. Open Lab11java and understand the code by tracing it line by line. There are some new things we have not seen before. Let us examine them now. 1. In this lab we will be using a text file for input. Whenever we do input/output using text files, we need to import java.io.”; import this package 2. public static void main(String args|) throws OException Whenever we open a file for reading some things could potentially go wrong. For example: The input file may not exist. The input file may have access restrictions. The input file may not be in the correct format. File may be residing in a remote server and a connection could not be established When you open a file for writing, the following things could go wrong: The disk may be write protected. The disk may be full The above mentioned issues could cause an IOEXception. At the end of the semester, we will cover exceptions, but for now, just think of exceptions as something outside he normal mode of execution. Whenever your code could cause an exception, we need to either deal with it or inform the compiler that your code could potentially cause an exception. Since we have not yet covered how to deal with an exception, we are telling the compiler that our code could cause an 1OException in the method header. That is what throws IOException in the main method header means. Only methods could throw exceptions not classes. 3. Scanner intile = new Scanner(new File(args[o)); – we have already seen in Lab 10, how command line arguments work. main method could take an array of Strings as argument (refer to Lab 10.html). Ihis line says that the input file name is passed as a command line argument as shown here. When you create a Scanner object to read from the standard input we use Scanner scnr = new Scanner(System.in);. You can use Scanner class to read akindly answer all the questionsComputer ScienceEngineering & TechnologyC++ ProgrammingCOM MISCShare Question
