Lecture 141:- C++ class for Diagonal Matrix

Let's create a C++ class for a diagonal matrix. The class will include methods to set and get elements, as well as display the diagonal matrix. We'll use a dynamic array to store the diagonal elements to allow flexibility in the matrix size. Here's the implementation:

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#include <iostream> class DiagonalMatrix { private:    int size;        // Size of the matrix    int* elements;   // Array to store diagonal elements public:    // Constructor to create a diagonal matrix of given size    DiagonalMatrix(int n) {        size = n;        elements = new int[size];        for (int i = 0; i < size; i++) {            elements[i] = 0;        }    }    // Destructor to deallocate memory    ~DiagonalMatrix() {        delete[] elements;    }    // Function to set an element at (i, i) position in the diagonal matrix    void setElement(int i, int value) {        if (i >= 0 && i < size) {            elements[i] = value;        } else {            std::cout << "Invalid index. Element not set." << std::endl;        }    }    // Function to get an element from (i, i) position in the diagonal matrix    int getElement(int i) {        if (i >= 0 && i < size) {            return elements[i];        } else {            std::cout << "Invalid index. Returning 0." << std::endl;            return 0;        }    }    // Function to display the diagonal matrix    void displayDiagonalMatrix() {        std::cout << "Diagonal Matrix:" << std::endl;        for (int i = 0; i < size; i++) {            for (int j = 0; j < size; j++) {                if (i == j) {                    std::cout << elements[i] << " ";                } else {                    std::cout << "0 ";                }            }            std::cout << std::endl;        }    } }; int main() {    DiagonalMatrix matrix(4);    matrix.setElement(0, 5);    matrix.setElement(1, 7);    matrix.setElement(2, 3);    matrix.setElement(3, 9);    matrix.displayDiagonalMatrix();    return 0; }

In this implementation, we have a class DiagonalMatrix, which encapsulates the diagonal matrix. The private data members include the size of the matrix (size) and a dynamic array (elements) to store the diagonal elements.

The constructor creates a diagonal matrix of the given size and initializes all elements to zero. The destructor deallocates the memory used by the dynamic array.

The setElement function sets an element at the (i, i) position in the diagonal matrix. The getElement function retrieves an element from the (i, i) position.

The displayDiagonalMatrix function displays the diagonal matrix with diagonal elements and zeros for non-diagonal elements.

In the main function, we create a diagonal matrix of size 4 and set its diagonal elements. Then, we display the matrix.

Output:

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Diagonal Matrix: 5 0 0 0 0 7 0 0 0 0 3 0 0 0 0 9

This C++ class allows you to create and work with a diagonal matrix easily. You can modify the matrix size and set elements as required.