matrixwithtest/MatrixProject/Matrix.cs

using MatrixProject.Exceptions;

namespace MatrixProject;

public struct Matrix
{
    private double[,] _data;

    public int Rows { get => _data.GetLength(0);}
    public int Columns { get => _data.GetLength(1);}


    public Matrix(int rows)
    {

        _data = new double[rows, rows];
        FillMatrixByNumber(0);

    }
    public Matrix(int rows, int columns) {
    
        _data = new double[rows,columns];
        FillMatrixByNumber(0);

    }
    public Matrix(int rows, int columns, int fillNumber)
    {
        
        _data = new double[rows, columns];
        FillMatrixByNumber(fillNumber);

    }

    public static Matrix operator +(Matrix matrix, Matrix matrixTwo) {
        if (matrix.Rows != matrixTwo.Rows ||
            matrix.Columns != matrixTwo.Columns) 
            throw new AdditionException("Строки и столбцы не совпадают");

        for (int i = 0; i < matrix.Rows; i++) {
            for (int j = 0; j < matrix.Columns; j++){
                matrix[i, j] += matrixTwo[i, j];
            }  
        }
        return matrix;
    }

    public static Matrix operator *(Matrix matrix, int scalar)
    {

        for (int i = 0; i < matrix.Rows; i++)
        {
            for (int j = 0; j < matrix.Columns; j++)
            {
                matrix[i, j] *= scalar;
            }
        }
        return matrix;
    }

    public double this[int row, int column] {
        get => _data[row,column];
        set => _data[row,column] = value;
    }

    private void FillMatrixByNumber(int number) {
        for (int i = 0; i < Rows; i++)
        {
            for (int j= 0; j < Columns; j++)
            {
                _data[i, j] = number;
            }
        }
    }
}