Soft20111 – Software Engineering Richard Hibberd – 88356 Portfolio task #6 – v2015.2 Portfolio 6 – coding challenge This task must be uploaded to your personal HG repository by 0845 on Monday 9th May 2016 (this is just before the final lab; the shoot-out is timed runs during the lab on that day). P6 is simply an exercise in writing efficient1 code; you will be assessed by the accuracy and speed of your program in processing a number of test cases. Your code file p6.cpp should supply an implementation for this function declared below; it should not declare nor implement a function main() Scoring is as follows and combines a mark for correct processing with a performance-related bonus, where the timings for calls to this function are added together and scaled as a percentage of the reference time. The reference time will be that returned by the function p6ACBC2, or the best student time. Correct processing is worth 8/15. A further 7 marks are available: • +1 if the time is within 300% of the reference time (up to 4 times slower) • +2 if the time is within 200% of the reference time (up to 3 times slower) • +3 if the time is within 100% of the reference time (up to 2 times slower) • +4 if the time is within 50% of the reference time • +5 if the time is within 20% of the reference time • +6 if the time is within 10% of the reference time • +7 if the time is within 5% of the reference time (or faster) • anything faster than the reference time, the 7 marks will be scaled pro rata3 You can use any source that will compile under gcc (g++) or clang; assembly language is allowed, but not recommended - the reference code is exclusively C++. Experience suggests that the best performance is likely to be achieved by careful analysis of the problem and design of the solution, rather than tricksy tweaking of the code4. 1 In this case, 'efficient' means w.r.t time (or fast). 2 This will be provided as object code for OSX (clang), gcc and VC12 (VS2013) 3 In this case, the winning student version will be worth > 100% (>15/15) 4 though experience also suggests that the module leader is far from infallible Soft20111 – Software Engineering Richard Hibberd – 88356 Portfolio task #6 – v2015.2 Portfolio 6 – coding challenge P6 is simply an exercise in writing efficient1 code; you will be assessed by the speed of your program in processing a number of test cases. Your code file p6.cpp should supply an implementation for the function declared below std::list & p6(unsigned long int factoriseMe); Do not address issues of process/thread allocation or other manipulations of processor resources – this is about your C++ p6 - the function The function returns (a reference to) a list of the prime factors of its parameter; it should reflect the following constraints • the list should be sequenced in descending order • if the parameter is 0 or 1, the list should be empty • any test of prime-ness must use values calculated as part of the function run-time (no embedded or loaded look-up tables • the parameter can be any value in the range 0 to numeric_limits::max() A Jenkins job will be available to provide reference results and to test your implementation.