Robotics Use Case - Industrial Robots

Code Structure

The code consists of the following files:

• Rectangle.h and Rectangle.cpp: These files define the Rectangle class, which represents a zone in the environment. It provides functions to set and get the zone's properties and check if a point is inside the zone or within a certain range of the zone.

• Robot.h and Robot.cpp: These files define the Robot class, which represents the industrial robot. It contains functions to set and get the robot's path and add points to the path.

• Point.h: This file defines the Point structure, which represents a 2D point with x and y coordinates.

• main.cpp: This file contains the main entry point of the program. It includes the necessary header files, defines the initializeZonesAndPath function, and implements the main algorithm of the program in the main() function.

Compilation and Execution

To compile and run the program, follow these steps:

1. Make sure you have a C++ compiler (such as GCC or Clang) installed on your system.

2. Download or clone the code files to your local machine.

3. Open a terminal or command prompt and navigate to the directory containing the code files.

4. Compile the code using the following command:

   g++ main.cpp Robot.cpp Rectangle.cpp -o program
   

This command compiles the source files and creates an executable file named program.

5. Run the program by executing the generated executable:

   ./program
   

The program will read the input file (input.txt by default), process the robot's path and the zones, and log the occurrences where the robot interacts with the zones.

Note: If you want to use a different input file, update the filename variable in the main() function of main.cpp before compiling.

Algorithm

The provided C++ code reads input from a text file, processes the data, and performs operations based on the input. Here is a step-by-step explanation of how the algorithm works:

1. File Initialization:

   • Include necessary header files and define the initializeZonesAndPath function.
   • Open the specified file using an std::ifstream object named inputFile. If the file fails to open, an exception is thrown.
   • Declare a string variable named line to store each line read from the file.

2. Lambda Function:

   • Define a lambda function named readNextNonEmptyLine to handle the task of reading the next non-empty line from the file.
   • Use a while loop with std::getline to read lines until a non-empty line is encountered.
   • The lambda function returns true if a non-empty line is found and false if there are no more lines to read.

3. Path Extraction:

   • Call the readNextNonEmptyLine function to check for a non-empty line.
   • If a non-empty line is found:
     • Process the line to extract pairs of x and y coordinates using an std::istringstream object named iss.
     • Add the extracted coordinates to the Robot object's path using the addPointToPath method.
   • If no non-empty line is found for the path information, an exception is thrown.

4. Zone Extraction:

   • Call the readNextNonEmptyLine function to check for a non-empty line.
   • If a non-empty line is found:
     • Process the line to extract the zone name, x and y coordinates, width, and height using the iss object.
     • Create Rectangle objects with the extracted information and add them to the zones vector.
   • If there is an issue with the input format (e.g., incorrect syntax or missing values), an exception is thrown.

5. File Closing:

   • Once all the lines have been processed, close the input file.

6. Main Function:

   • Create a Robot object named robot, declare a filename variable, and initialize an empty vector of Rectangle objects named zones.
   • Call the initializeZonesAndPath function, passing the filename, zones vector, and robot object as arguments.
   • This function reads the input file and populates the robot object with path information and the zones vector with zone information.

7. Flag Initialization:

   • Create a vector of characters named flags with the same size as the zones vector.
   • This vector will be used to track the status of each zone.

8. Zone Tracking:

   How it works: If the point is not within a 1-meter range, keep the flag as false. Once it enters the 1-meter range, check the flag. If the flag is false, it means the point was not previously in the range, so print "entering". If the flag is true, it means the point was already inside the zone, so print "leaving". If the point is inside the zone, print "inside" and set/keep the flag true in order to track its state when the point is outside the zone but within the 1-meter range.

   • Initialize an integer variable named count to zero. It will keep track of the index of the current zone while iterating over the zones vector.
   • Enter a nested loop:
     • The outer loop iterates over each point in the robot object's path.
     • The inner loop iterates over each Rectangle object in the zones vector.
     • For each point and zone pair:
       • Check if the point is within the range of the zone by calling the checkIfPointWithinRange method of the Rectangle object.
       • If the point is within the zone's range:
         • Check if the point is inside the zone by calling the checkIfPointInZone method.
         • If the point is inside the zone:
           • Print a message indicating that the point is inside the current zone's name.
           • Set the corresponding flag in the flags vector to true if it is not already set.
         • If the point is outside the zone but within its range:
           • Check the corresponding flag in the flags vector.
           • If the flag is set, print a message indicating that the point is exiting the current zone.
           • If the flag is not set, print a message indicating that the point is about to enter the current zone.
       • If the point is outside the zone's range, reset the corresponding flag in the flags vector to false.
       • Increment the count variable to move to the next zone.
     • After processing all points for a given zone, reset the count variable to zero and print a newline character.

9. Exception Handling:

   • Use a try-catch block to catch any exceptions thrown during the execution of the program.
   • If an exception occurs, print an error message indicating the exception's details.

This algorithm utilizes a lambda function, readNextNonEmptyLine, to handle the repetitive task of reading the next non-empty line from the input file. In SecondVersion branch, I added the use of smart pointers.

Extra Modern CPP features Added to FirstVersion branch

1. Lambda Functions

2. Range-based for loop

3. Auto type inference

   I used the auto keyword to automatically deduce the type of the variable in zones vector: std::unique_ptr<Rectangle>.

4. Initializer Lists

   Initialize objects using braced initializer lists ({}) for uniform and concise initialization.

5. Using std::optional

   Instead of using flags to represent the state of zones, I used std::optional to provide a more expressive and type-safe representation. It allows me to express the possibility of having a value (true or false) or having no value (std::nullopt).

6. Smart Pointers

   In this modified code, the zones vector is now a vector of std::unique_ptr<Rectangle>. The initializeZonesAndPath function uses std::make_unique to dynamically allocate Rectangle objects and stores them as unique pointers in the zones vector. The deallocation of memory for the Rectangle objects is automatically handled by the std::unique_ptr when the vector goes out of scope.

   In the code, I made the following changes:

   • Changed the zones vector to std::vector<std::unique_ptr<Rectangle>> zones to store Rectangle objects as std::unique_ptr. It ensures that the dynamically allocated objects are properly deallocated when they are no longer needed. By using std::unique_ptr, I avoid the need to manually call delete on the objects.

   • Modified the initializeZonesAndPath function to use std::make_unique: Instead of directly creating Rectangle objects and adding them to the zones vector, I used std::make_unique to store them as std::unique_ptr<Rectangle>.

   • Changed the iteration over zones to use const auto& z: When iterating over the zones vector, I used const auto& z instead of copying the std::unique_ptr<Rectangle> objects. This avoids unnecessary copying of the smart pointers and improves performance.

   • In the previous code, z.checkIfPointWithinRange(p) was used to call the member function checkIfPointWithinRange on the Rectangle object z. However, in the modified code that uses smart pointers, we store Rectangle objects as std::unique_ptr<Rectangle> in the zones vector. To access the member functions of the Rectangle objects through the smart pointer, we use the arrow operator (->). The arrow operator is used to dereference the smart pointer and access the member functions. It is equivalent to (*z).checkIfPointWithinRange(p), where the * operator is used to dereference the smart pointer and access the underlying object.