C++代写：OOP244 Dynamic Memory

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练习Dynamic Memory的分配与释放，以及Function Overload等基本语法。

Function Overload

Learning Outcomes

Upon successful completion of this workshop, you will have demonstrated the abilities to:

  • allocate and deallocate dynamic memory for an array
  • overload functions
  • create and use references

Compiling and Testing Your Program

All your code should be compiled using this command on matrix:

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g++ -Wall -std=c++11 -g -o ws file1.cpp file2.cpp ...
  • -Wall: the compiler will report all warnings
  • -std=c++11: the code will be compiled using the C++11 standard
  • -g: the executable file will contain debugging symbols, allowing valgrind to create better reports
  • -o ws: the compiled application will be named ws

After compiling and testing your code, run your program as follows to check for possible memory leaks (assuming your executable name is ws):

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valgrind --show-error-list=yes --leak-check=full --show-leak-kinds=all --track-origins=yes ws
  • --show-error-list=yes: show the list of detected errors
  • --leak-check=full: check for all types of memory problems
  • --show-leak-kinds=all: show all types of memory leaks identified (enabled by the previous flag)
  • --track-origins=yes: tracks the origin of uninitialized values (g++ must use -g flag for compilation, so the information displayed here is meaningful).

To check the output, use a program that can compare text files. Search online for such a program for your platform, or use diff available on matrix.

Note: All the code written in workshops and the project must be implemented in the sdds namespace, unless instructed otherwise.

Custom code submission

If you have any additional custom code, (i.e. functions, classes etc) that you want to reuse in the workshop save them under a module called Utils (Utils.cpp and Utils.h) and submit them with your workshop using the instructions in the Submitting Utils Module section.

Part 1

Customers ‘ main report is a program that reads records of behavioral profiles of using Android applications of a number of Customers from a file and holds these records in a dynamically allocated array of Customers. (Each record holds the app’s identifier (Package_name), The user’s identifier (user_id), spent time in hours (timeinhours) , day of the year (dayofyear), spent foreground Wi-Fi network connection time(ms)(Fwifitime), and day of week (dayofweek), spent foreground cellular network connection time(ms) (Fctime), in a .csv file format.)
After loading all the information into a dynamic array of Customers, the program will groups the records based on the user_id in ascending order

LAB Execution example

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Records were retrieved successfully
Data records were grouped by the user id successfully
User id, timeinhours, Fctime, Fwifitime, Package Name
.....................................................
0,1.49325,369926,5005762,com.tencent.mm
0,1.35947,172756,4721320,com.tencent.mm
0,1.66986,1221,6010276,com.UCMobile
5,1.60287,5722288,48042,com.sina.weibo
5,1.92426,260011,6667309,com.tencent.mm
5,1.47877,2089902,3233672,com.UCMobile
9,1.02618,288007,3406229,com.digiplex.game
9,1.23554,59991,4387945,com.tencent.mm
9,12.9425,2190642,44402341,com.tencent.mm
9,1.21251,2544077,1820967,com.tencent.qqmusic
.....................................................
Data was successfully printed
Dynamically allocated memory was successfully deallocated

This program is partially developed, and you can find all the files in the lab directory. Your task is to complete the code as stated in the comments in the source code.

The Code

The structure holding the customers’ records is designed as follows:

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struct Customers {
     char* Package_Name;
     int user_id;
     double timeinhours;
     int dayofyear;
     int Fwifitime;
     int Fctime;
     char dayofweek;
 };

In addition to holding the customer records in an dynamically allocated array of Customers, each Package’s name is also held in a dynamically allocated Cstring in the Customer structure.

Data file

Here is a sample of the data csv file in the following format:

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dayofweek, user_id, timeinhours, dayofyear, Fwifitime, Fctime, Package_Name<NEWLINE>

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T	2	0.030551111	121	1989	 107995	  com.android.chrome
F	0	1.669860278	122	6010276	 1221	  com.UCMobile
F	5	1.478770556	122	3233672	 2089902  com.UCMobile
S	0	0.721798889	124	248535	 2349941  com.UCMobile
S	8	0.098520556	124	354674	 0	  com.uu.uunavi
S	2	0.087850556	124	0	 316262	  com.zhihu.android
M	3	0.107762222	125	0	 387944	  cn.coupon.kfc
M	8	6.175799722	125	20623140 1609739  com.android.chrome

The Program Modules

There are three modules in the program:
Tools, Package and main

Tools Module

The following three functions are already implemented in the Tools module:

  1. openFile_r
    Opens the data file for reading
  2. closefile
    Closes the data file
  3. noOfTraces
    Returns an integer that is the number of records in the opened and read file; use this function in the Package module to determine the size of the dynamic array of customers.

Your coding tasks in the Tools module:

Implement 4 overloads of a function called read

  1. read function for the Package name:
    When success, returns a Cstring argument to send back the name of the Package.
    Use the following fscanf function to read the name of the Package from the file. 

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    fscanf(fp, "%60[^\n]\n", ......

  2. read function for the user_id, dayofyear, Fwifitime and Fctime :
    When success, returns a reference argument to an integer to pass back the user id, dayofyear,Fwifitime and Fctime.
    Use the following fscanf function to read the user_id, dayofyear, Fwifitime and Fctime from the file and return true if it returns 1. 

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    fscanf(fp, "%d,".......

  3. read function for the timeinhours:
    When success, returns a reference argument to a doubler number to pass back the timeinhours.
    Use the following fscanf function to read the timeinhours from the file. 

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    fscanf(fp, "%lf,",......

  4. read function for the dayofweek:
    When success, returns a reference argument to a char to pass back the dayofweek.
    Use the following fscanf function to read the dayofweek from the file. 

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    fscanf(fp, "%[^ \t\n\r\v\f,]%*c",......

Package Module

The Package Module has two global variables:

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int no_of_traces;

no_of_traces should hold the number of records read from the file and thus it should be used later to allocate the dynamic array of Customers.

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Customers* users;

This Customers pointer should point to the dynamic array of users.

Functions

The following function is already implemented in the Package module:
grouptTraces()
This function groups the records in the dynamic array of users based on the user_id in ascending order.

Complete the implementation of the following two functions:

  1. loadTraces
    This overload of the loadTraces function returns a bool and receives a Customers reference.
    In a local array of 50 characters, it will try to read the Package name from the file. If successful it will find the actual length of the Package name using the strlen function and then add one to the length (for null termination) and allocate the same amount of characters in the name of the Customers reference.
    Then it will copy the read name (from the local character array) into the newly allocated name of the Customers reference using strcpy.
    If all the reads were successful, it will return true, otherwise false.
  2. loadTraces
    This overload of the loadTraces function loads all the users records into the Customers array and returns a bool for success and has no arguments.
    First open the data file.
    Then set the number of users to the number of records in the file and then allocate a dynamic array of users pointed by the global Customers pointer; “users” to the number of the records in the file.
    Then load the users one by one from the file into the dynamic array of users.
    If the number of read records does not match the number of records, display the following error message and return false.
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    Error reading the records, Check the data file.

Otherwise return true.

Implement the following two functions:

  1. display
    This function does not receive or return anything.
    This function displays customer records one by one (each record in a new row) based on the following condition: (timeinhours > 1.0 and dayofweek == ‘F’).
    See the sample output.
  2. deallocateMemory
    This function does not return or receive anything.
    In a loop go through all the elements of the users array and deallocate the dynamic Package_Name of each user. Then deallocate the whole users array.

main Module.

Please do not modify the main Module.

PART 1 Submission (lab)

Files to submit:

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main.cpp
Package.h
Package.cpp
Tools.h
Tools.cpp
....

Custom code submission

If you have any additional custom code, (i.e. functions, classes etc) that you want to reuse in this workshop save them under a module called Utils (Utils.cpp and Utils.h) and submit them with your workshop using the instructions in the Submitting Utils Module section.

Data Entry

No data entry

LAB Submission (part 1)

To test and demonstrate execution of your program use the same data as shown in the LAB Execution example.

Then, run the following command from your matrix account

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~profname.proflastname/submit 2??/wX/pY_sss  <ENTER>
  • Replace ?? with your subject code (00 or 44)
  • Replace X with Workshop number: [1 to 10]
  • Replace Y with the part number: [1 or 2]
  • Replace sss with the section: [naa, nbb, nra, zaa, etc...]

and follow the instructions.

Submitting Utils Module

To have your custom Utils module compiled with your workshop and submitted, add a u to the part number of your workshop (i.e up1_sss for part one and up2_sss for part two) and issue the following submission command instead of the above:

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~profname.proflastname/submit 2??/w#/upX_sss

See Custom Code Submission section for more detail

DIY

Twitter is a social media site whose primary purpose is to connect people and allow them to share their thoughts with a big audience. Complete a program that receives tweets information for an unknown number of users.
This information includes user_name, likes_count, retweets_count, replies_count, and share_videos (Y/N) on Twitter. At the end of the entry process, the user presses enter instead of entering the user name to end the program. This will end the program and display all the tweets’ reports for the entered users.

Tester Program (main.cpp)

This module is fully provided. Please do not change any of its code. Review it and make sure you understand how the functions that you have developed are being used.

Implementation

This application is implemented in three modules:

  • main Module (fully provided)
  • Tools Module (fully provided)
  • Customer Module (implement)

Your task is to complete the implementation of the Customer module to provide the functions needed in the main module.

You may freely use or copy any logic or code needed from the LAB section

Structs to be used:

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struct Customers {
    char user_name[21];
    int retweets_count;;
    int likes_count;
    int replies_count;
    char share_videos;
};
struct CustomersRecord {
    Customers* ptr_rec;  // Dynamically holds the customers' tweets report.
    int noOfRecords;
};

Required functions (mandatory)

Implement 2 overloads of a function called EmptyRecord

  1. void EmptyRecord(………..);
    Sets Customer data members to an empty state
  2. void EmptyRecord(………..);
    Sets CustomersRecord data members to an empty state

Implement the follwoing five functions

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bool read(Customers& rec);

Requests to enter "user name: " and then reads a CString into the name of the Customer reference.
If the user enters a value of the user name, then it will read the likes_count, retweets_count, replies_count, and share_videos of the Customer and returns true. Otherwise, if the CString for the name is empty after entry, the function returns false.

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void read(char* str, int len);

Reads a CString into the str pointer up to len characters.

This function is already implemented and is provided in the Customer module

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void addCustomer(CustomersRecord& t_rec, const Customers& c_rec);

Adds a Customer to the dynamically allocated memory of customers in CustomersRecord

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void display(const Customers& c_rec);

Prints the Customer information as follows:

  • user name
  • comma and space ", "
  • likes
  • comma and space ", "
  • re-tweets
  • comma and space ", "
  • replies
  • comma and space ", "
  • share videos (y/n)
  • new line "\n "
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void display(const CustomersRecord& t_rec)

It prints a row number with a period before each user name. Then, it prints all the customers’ records.

Execution Sample

correct_output.txt

Reflection

Study your final solutions for each deliverable of the workshop, reread the related parts of the course notes, and make sure that you have understood the concepts covered by this workshop. This should take no less than 30 minutes of your time and the result is suggested to be at least 150 words in length.
Create a file named reflect.txt that contains your detailed description of the topics that you have learned in completing this workshop and mention any issues that caused you difficulty.

Part 2 Submission (DIY)

Files to submit:

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main.cpp (please do not modify this file).
Customer.cpp
Customer.h
Tools.cpp
Tools.h
....

Data Entry

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zebaism
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rohanv
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frank
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desibrah
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sheetut
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<ENTER>

Submission Process:

Upload the files listed above to your matrix account. Compile and run your code using the g++ compiler as shown in Compiling and Testing Your Program and make sure that everything works properly.

Then, run the following command from your matrix account

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~profname.proflastname/submit 2??/wX/pY_sss  <ENTER>
  • Replace ?? with your subject code (00 or 44)
  • Replace X with Workshop number: [1 to 10]
  • Replace Y with the part number: [1 or 2]
  • Replace sss with the section: [naa, nbb, nra, zaa, etc...]

and follow the instructions.

Submitting Utils Module

To have your custom Utils module compiled with your workshop and submitted, add a u to the part number of your workshop (i.e up1 for part one and up2 for part two) and issue the following submission command instead of the above:

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~profname.proflastname/submit 2??/w#/upX

See Custom Code Submission section for more detail