using System;

namespace Project7_27
{
	class Matrix
	{		
		public double[ , ] m; //2-dimensional array to hold matrix entries.

		/*
		 *  Constructor Input: 
		 *  n : dimension size of the square matrix
		 *  val : an array of arrays to initialize m 
		 */
		public Matrix( int n, double[][] val) 
		{
			m = new double[n, n];
		
			//Assign matrix entries row by row.
			for(int i=0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					m[i,j] = val[i][j];
				}
			}
		}		
		
		public static Matrix Add( Matrix x, Matrix y)
		{
			double[ , ] m1, m2;
			m1 = x.m; //matrix values of x
			m2 = y.m; //matrix values of y
			int n = m1.GetLength(0); //x and y are nxn matrices
			
			//m3: an array of arrays to hold the sum of m1 and m2.
			double[][] m3 = new double[n][];
			m3[0] = new double[n];
			m3[1] = new double[n];
			m3[2] = new double[n];

			for(int i=0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					m3[i][j] = m1[i,j] + m2[i,j];
				}
			}
			
			//Construt a nxn matrix z from m3 and return z.
			Matrix z = new Matrix(n, m3);
			return z;
		}
		public static Matrix Subtract (Matrix x, Matrix y)
		{
			double[ , ] m1, m2;
			m1 = x.m; //matrix values of x
			m2 = y.m; //matrix values of y
			int n = m1.GetLength(0); //x and y are nxn matrices
			
			//m3: an array of arrays to hold the sum of m1 and m2.
			double[][] m3 = new double[n][];
			m3[0] = new double[n];
			m3[1] = new double[n];
			m3[2] = new double[n];

			for(int i=0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					m3[i][j] = m1[i,j] - m2[i,j];
				}
			}
			
			//Construt a nxn matrix z from m3 and return z.
			Matrix z = new Matrix(n, m3);
			return z;
		}

		public static Matrix ScalarMultiply (Matrix x, double s)
		{
			double[ , ] m1;
			m1 = x.m; //matrix values of x			
			int n = m1.GetLength(0); //x is nxn matrice
			
			//m3: an array of arrays to hold the sum of m1 and m2.
			double[][] m3 = new double[n][];
			m3[0] = new double[n];
			m3[1] = new double[n];
			m3[2] = new double[n];

			for(int i=0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					m3[i][j] = m1[i,j] * s;
				}
			}
			
			//Construt a nxn matrix z from m3 and return z.
			Matrix z = new Matrix(n, m3);
			return z;
			
		}
		public void Print()
		{
			int n = m.GetLength(0);
			for(int i=0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					Console.Write(m[i,j]+"\t");
				}
				Console.WriteLine();
			}
			Console.WriteLine();
		}

	}

	class TestMatrix
	{
		public static void Main()
		{
			//v1 - an array of arrays to create matrix x
			double[][] v1 = new double[3][];
			v1[0] = new double[3]{2,5,4};
			v1[1] = new double[3]{-2,7,9};
			v1[2] = new double[3]{8,-3,2};

			//v2 - an array of arrays to create matrix y
			double [][]v2 = new double[3][];
			v2[0] = new double[3]{2,5,4};
			v2[1] = new double[3]{-2,7,9};
			v2[2] = new double[3]{8,-3,2};

			Matrix x, y, z;
			x = new Matrix(3, v1);
			y = new Matrix(3, v2);
			Console.WriteLine("Matrix x: ");
			x.Print();
			Console.WriteLine("Matrix y: ");
			y.Print();
			
			//Add matrix x and y
			z = Matrix.Add(x,y);
			Console.WriteLine("x + y: ");
			z.Print();

			//Subtract matrix x and y
			z = Matrix.Subtract(x,y);
			Console.WriteLine("x - y: ");
			z.Print();

			//Multiply matrix x with a scale value.
			z = Matrix.ScalarMultiply(x,2.0);
			Console.WriteLine("x * 2.0: ");
			z.Print();
		}
	}
}