Lesson 3
Transposing Matrices in C#
Introduction

Hello there! Are you ready to enhance your C# programming skills with another exciting exercise? In this unit, we are plunging into the world of matrices. More specifically, we'll be transposing a given matrix. Let's dive into this matrix manipulation without delay!

Task Statement

To begin, let's elaborate on the task at hand. You are required to write a C# function named TransformMatrix(). This function will accept a 2D int array (which represents a matrix) that contains integers as inputs. Your responsibility is to return another 2D int array, which is the transposed version of the given matrix.

Remember, when we mention 'transposing a matrix,' we are referring to the process of switching its rows and columns. In other words, all the rows of the original matrix should be converted into columns in the transposed matrix, and vice versa.

For instance, if the original matrix (input 2D array) is:

C#
1int[,] matrix = { 2 {1, 2, 3}, 3 {4, 5, 6} 4};

Then the transposed matrix (output 2D array) will be:

C#
1int[,] transposed = { 2 {1, 4}, 3 {2, 5}, 4 {3, 6} 5};

It is vital for your result to maintain the integrity of the data type present in the original matrix. In layman's terms, the values seen in the input matrix are integers, and they should be integers in the output matrix as well.

Solution Building: Step 1

The initial step of building our solution involves determining the dimensions of the matrix. We need to know the number of rows and columns present in it. In C#, the GetLength method of the array class can offer this information. The number of rows is the length of the array in the first dimension (dimension 0), and the number of columns is the length of the array in the second dimension (dimension 1).

C#
1class Solution { 2 3 public static int[,] TransformMatrix(int[,] matrix) { 4 int rows = matrix.GetLength(0); 5 int cols = matrix.GetLength(1); 6 } 7}
Solution Building: Step 2

The subsequent step is to create a "placeholder" for the transposed matrix that aligns with its required dimensions. This will be a new 2D array, but with the number of rows and columns swapped. Initially, we can populate this matrix with all zeros.

C#
1class Solution { 2 3 public static int[,] TransformMatrix(int[,] matrix) { 4 int rows = matrix.GetLength(0); 5 int cols = matrix.GetLength(1); 6 int[,] result = new int[cols, rows]; 7 } 8}
Solution Building: Step 3

It's time to get to the crux of the matter — transposing the matrix. For every element in the original matrix, we want to move it from the ith row and jth column to the jth row and ith column of the transposed matrix. A straightforward nested for-loop can effortlessly execute this swap for all elements of the matrix.

C#
1class Solution { 2 3 public static int[,] TransformMatrix(int[,] matrix) { 4 int rows = matrix.GetLength(0); 5 int cols = matrix.GetLength(1); 6 int[,] result = new int[cols, rows]; 7 8 for (int i = 0; i < rows; ++i) { 9 for (int j = 0; j < cols; ++j) { 10 result[j, i] = matrix[i, j]; 11 } 12 } 13 return result; 14 } 15 16 public static void Main(string[] args) { 17 // Initial matrix (2D array) 18 int[,] matrix = { 19 {1, 2, 3}, 20 {4, 5, 6} 21 }; 22 23 // Call our function on the matrix and output the result 24 int[,] transposed = TransformMatrix(matrix); 25 for (int i = 0; i < transposed.GetLength(0); ++i) { 26 for (int j = 0; j < transposed.GetLength(1); ++j) { 27 Console.Write(transposed[i, j] + " "); 28 } 29 Console.WriteLine(); 30 } 31 } 32}

This step concludes our solution!

Lesson Summary

With this, we've brought this lesson to a close! Congratulations on successfully implementing a function that can transpose matrices! This task is not simple, but by accomplishing it, you've exhibited your understanding of and proficiency in C# multidimensional arrays, for-loops, and the concept of matrix transposition.

Your hard work continues, though. Now that you have acquired this valuable skill, it's time to reinforce it with more practice. During the next session, you will encounter practice problems that build on this concept. So, get ready and start coding!

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