Question

How to print the boundary elements of a matrix in C#

Answer 1

using System;

class MatrixBoundary
{
    static void PrintMatrixBoundaries(int[,] matrix, int rows, int cols) {
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                // Check if the element is on the boundary
                if (i == 0 || j == 0 || i == rows - 1 || j == cols - 1) {
                    Console.Write(matrix[i, j] + " ");
                }
            }
        }
    }

    static void Main()
    {
        int[,] matrix = {
            { 1,  2,  3,  4,  5 },
            { 6,  7,  8,  9, 10 },
            {11, 12, 13, 14, 15 },
            {16, 17, 18, 19, 20 }
        };

        int rows = matrix.GetLength(0);
        int cols = matrix.GetLength(1);

        PrintMatrixBoundaries(matrix, rows, cols);
    }
}



/*
run:

1 2 3 4 5 6 10 11 15 16 17 18 19 20 

*/

 

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Answer 2

using System;

class MatrixBoundary
{
    static void PrintMatrixBoundaries(int[,] matrix, int rows, int cols) {
        // Print first row
        for (int j = 0; j < cols; j++)
            Console.Write(matrix[0, j] + " ");

        // Print last column
        for (int i = 1; i < rows; i++)
            Console.Write(matrix[i, cols - 1] + " ");

        // Print last row in reverse
        for (int j = cols - 2; j >= 0; j--)
            Console.Write(matrix[rows - 1, j] + " ");

        // Print first column upwards
        for (int i = rows - 2; i > 0; i--)
            Console.Write(matrix[i, 0] + " ");
    }

    static void Main()
    {
        int[,] matrix = {
            { 1,  2,  3,  4,  5 },
            { 6,  7,  8,  9, 10 },
            {11, 12, 13, 14, 15 },
            {16, 17, 18, 19, 20 }
        };

        int rows = matrix.GetLength(0);
        int cols = matrix.GetLength(1);

        PrintMatrixBoundaries(matrix, rows, cols);
    }
}



/*
run:

1 2 3 4 5 10 15 20 19 18 17 16 11 6 

*/

 

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