Question

1.Write a Java program that computes the average of the values of a row in a twodimensional array. You should create a method with the following header: public static double averageRow(double[][] array, int row) Write a test program that reads a matrix from the user and a row index to calculate the average on. Print the result.

2.A square matrix is said to be an upper triangular matrix if the value of the cell is 0 when row > column. For example, 2 1 4 0 3 −1 0 0 −2 is an upper triangular matrix. Write a method that will check if a matrix is an upper triangular matrix: public static boolean isUpperTriangular(double[][] array) Write a test program to test your method.

Java please thank you

Answer 1

/*
 *  Java Program array row average, upper triangle check
 */

public class Main
{
  private static final int M = 4;
  private static final int N = 4;

  static double averageRow(double[][] array, int row)
  {
    double sum = 0.0;
    for (int i = 0; i < N; ++i) {
        sum = sum + array[row][i];
    }
    return sum/N;
  }

  public static Boolean isUpperTriangular(double array[][])
  {
    for (int i = 1; i < M ; i++)
      for (int j = 0; j < i; j++)
        if (array[i][j] != 0)
          return false;
    return true;
  }

  public static void main(String argc[]){
    double[][] mat = { {1.1, 3.3, 5.5, 3.3},
                    {0.0, 4.4, 6.6, 2.2},
                    {0.0, 0.0, 2.2, 5.5},
                    {0.0, 0.0, 0.0, 6.6} };

    System.out.println("Average of 2 row: " + averageRow(mat, 2));

    if (isUpperTriangular(mat))
      System.out.println("Yes");
    else
      System.out.println("No");
  }
}