C，loops, if statements, functions, and arrays。
Learning Outcomes
In this project you will demonstrate your understanding of loops, if statements, functions, and arrays, by writing a program that first reads a file of text data, and then performs a range of processing tasks on the data. The sample solution that will be provided to you after the assignment has been completed will also make use of structures (covered in Chapter 8), and you may do likewise if you wish. But there is no requirement for you to make use of struct types, and they will not have been covered in lectures before the due date.
Sequential Data
Scientific and engineering datasets are often stored in text files using comma separated values (.csv format) or tab separated values (.tsv format), usually with a header line describing the contents of the columns. A standard processing framework on such data is to first read the complete set of input rows into arrays, one array per column of data, and then pass those arrays (and a buddy variable) into functions that perform various computations based on the arrays.
Your task in this project is to compute delivery sequences for Alistazon, a start-up company that is planning to use drones to deliver parcels to customers. Each batch of deliveries is described by a file that has one row of numbers for each package that has to be delivered. In the examples that follow we suppose that the data file drones0.tsv contains these values in tab-separated format:
x y kg 150.6 -185.2 2.5 113.9 500.9 4.15 -31.6 51.9 4.31 -58.2 190.3 5.7 -27.8 312.6 1.95
There will always be a single header line in all input files, and then rows of three values separated by “tab” characters (‘\t’ in C). Once the first line has been bypassed (write a function that reads characters and throws them away until it reads and throws away a newline character, ‘\n’), each data line can be read using scanf(“%lf%lf%lf”,…). The three values in each row represent an (x,y) location on a east-west/north-south grid, in units of meters relative to an origin, and a package weight, in units of kilograms. This example file and another one drones1.tsv can be copied from http://people.eng. unimelb.edu.au/ammoffat/teaching/20005/ass1/.
Stage 1 - Control of Reading and Printing
The first version of your program should read the entire input dataset into a collection of three parallel arrays (or, if you are adventurous, an array of struct), counting the data rows as they are read. The heading line should be discarded and is not required for any of the subsequent processing steps. Once the entire dataset has been read, your program should print the total number of data lines that were read, the first and last of the input records, and the total of the package weights. The output from your program for this stage for file drones0.tsv must be:
mac: myass1 lt; drones0.tsv S1, total data lines: 5 S1, first data line : x=150.6, y=-185.2, kg=2.50 S1, final data line : x=-27.8, y=312.6, kg=1.95 S1, total to deliver: 18.61 kg
Note that the input is to be read from stdin in the usual manner, via “[“ input redirection at the shell level; and that you must not make use of the file manipulation functions described in Chapter 11. No prompts are to be written.
You may (and should) assume that at most 999 data lines will occur in any input file, not counting the header line. Note that to obtain full marks you need to exactly reproduce the required output lines. Full output examples can be found on the FAQ page linked from the LMS.
Stage 2 - Sequential Processing
The Alistazon drones are battery powered, and can carry up to 5.8 kilograms each in addition to the 3.8 kilogram weight of the drone itself. (Future models may be able to carry more, but this is the current limit.) When the drone is carrying a payload of w kilograms, a fully-charged battery pack allows the drone to safely fly a total of 6300/(3.8+w) meters. That is, an unladen drone can safely travel a total of 6300/3.8 = 1657.9 meters, whereas a fully laden drone can only safely fly 6300/(3.8+5.8) = 656.3 meters. The drones fly at a constant speed of 4.2 meters/second, regardless of what load they are carrying, and always fly in a straight line from one specified location to another.
As an example, suppose that a fully-charged drone starts at location (0,0) and is to carry out the first delivery in the list in drones0.txt.
On the outward trip, before the delivery takes place made, the drone plus package has a weight of 3.8 + 2.5 = 6.3 kg, and hence the drone range is given by 6300/6.3 = 1000.0 meters. That is, the outward trip to the delivery point will consume 238.7/1000.0 = 23.9% of the available battery power. On the return trip back to the origin, after the delivery has been made, the drone is lighter, and consumes another 238.7/1657.9 = 14.4% of the battery capacity. The round trip to complete the first delivery will have a flight time of 2238.7/4.2 = 113.7 seconds, and will consume a total of 23.9+14.4% = 38.3% of a full battery charge.
Add further functionality to your program to carry out these calculations for each package, and to tell the operators when the battery pack needs to be changed. You should assume that each delivery commences at and returns to the origin (0,0), and that the packages are delivered in the same order they are listed in the data file. For drones0.tsv, your output from this stage should be:
S2, package= 0, distance= 238.7m, battery out=23.9%, battery ret=14.4% S2, change the battery S2, package= 1, distance= 513.7m, battery out=64.8%, battery ret=31.0% S2, change the battery S2, package= 2, distance= 60.8m, battery out= 7.8%, battery ret= 3.7% S2, package= 3, distance= 199.0m, battery out=30.0%, battery ret=12.0% S2, change the battery S2, package= 4, distance= 313.8m, battery out=28.6%, battery ret=18.9% S2, total batteries required: 4 S2, total flight distance=2652.0 meters, total flight time= 631 seconds
Note how the large demand associated with package 1 forces a battery change straight after package 0, even though less than half the battery capacity was used. In contrast, packages 2 and 3 are able to be delivered on a single battery.
Before implementing this step, you should read the rest of the specification, to understand what else will be required as your program develops. Code should be shared between the stages through the use of functions wherever it is possible to do so. In particular, there shouldn’t be long (or even short) stretches of repeated or similar code appearing in different places in your program. Functions should also be used to break up long runs of code, to make them more understandable, even if those functions are only called once. As a general rule of thumb, functions shouldn’t be longer than a single screen in the editor. If they are, break that code up further into smaller functions. It is also completely ok to have functions that are just one or two lines long.
Your program should print an error message and exit if any of the packages would require more than 100% of a fully charged battery to be delivered, or if any package weighs more than 5.8 kilograms.
Stage 3 - Non-Sequential Processing
Ok, so now let’s try and make better use of each battery. Add further functionality to your program so that after each delivery has been completed, all of the remaining undelivered packages are considered in turn, and if any of them can be delivered using the current battery, that delivery is carried out next.
That is, for each fully charged battery, you should consider the entire list of packages in order, starting at the beginning, and each package that can be delivered using the power still available in that battery should be delivered. The battery is changed to a fresh one only when there are no remaining packages that can be delivered using the old battery.
The required output for drones0.tsv is (hint, hint) similar in format to the Stage 2 output:
S3, package= 0, distance= 238.7m, battery out=23.9%, battery ret=14.4% S3, package= 2, distance= 60.8m, battery out= 7.8%, battery ret= 3.7% S3, package= 3, distance= 199.0m, battery out=30.0%, battery ret=12.0% S3, change the battery S3, package= 1, distance= 513.7m, battery out=64.8%, battery ret=31.0% S3, change the battery S3, package= 4, distance= 313.8m, battery out=28.6%, battery ret=18.9% S3, total batteries required: 3 S3, total flight distance=2652.0 meters, total flight time= 631 seconds
Stage 4 - A Further Generalization
Stages 2 and 3 assumed that all deliveries were to start from the origin point at (0,0), maybe because that is where the Alistazon warehouse is located. But a smart employee (that had taken comp20005 while studying at University) has pointed out that maybe it could be better to put a batch of deliveries into a van, drive to some more useful location, and then do the deliveries from that point. They suggest that an appropriate starting point could be found by computing as a kind of “centroid” location of the n delivery locations (xi,yi). The same package delivery approach as was used for Stage 3 would then be followed. The required output for this stage for drones0.tsv is:
S4, centroid location x= 29.4m, y= 174.1m S4, package= 0, distance= 379.2m, battery out=37.9%, battery ret=22.9% S4, package= 2, distance= 136.6m, battery out=17.6%, battery ret= 8.2% S4, change the battery S4, package= 1, distance= 337.6m, battery out=42.6%, battery ret=20.4% S4, package= 3, distance= 89.1m, battery out=13.4%, battery ret= 5.4% S4, change the battery S4, package= 4, distance= 149.8m, battery out=13.7%, battery ret= 9.0% S4, total batteries required: 3 S4, total flight distance=2184.5 meters, total flight time= 520 seconds
The FAQ page contains links to full output examples that show how the output from the stages is to appear overall. Note the final output line at the end of each execution it is also required.