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 game 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 std::vector (which represents a matrix) that contains integers as inputs. Your responsibility is to return another 2D std::vector, 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 convert into columns in the transposed matrix, and vice versa. For instance, if the original matrix (input 2D std::vector) is: C++ std::vector<std::vector<int>> matrix = {{1, 2, 3}, {4, 5, 6}}; Then the transposed matrix (output 2D std::vector) will be: C++ std::vector<std::vector<int>> transposed = {{1, 4}, {2, 5}, {3, 6}}; It is vital for your result to maintain the integrity of the data type that is 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 .size() method of std::vector can offer this information. The number of rows is simply the size of the matrix (the outer vector), and the number of columns matches the size of any of the inner vectors. C++ #include <iostream> #include <vector> std::vector<std::vector<int>> transformMatrix(const std::vector<std::vector<int>>& matrix) {int rows = matrix.size(); int cols = rows > 0 ? matrix[0].size() : 0;}

Solution Building: Step 2

The subsequent step is to create a "placeholder" for the transposed matrix that is in alignment with its required dimensions. This will be a new 2D std::vector, but with the number of rows and columns swapped. Initially, we can populate this matrix with all zeros. C++ #include <iostream> #include <vector> std::vector<std::vector<int>> transformMatrix(const std::vector<std::vector<int>>& matrix) {int rows = matrix.size(); int cols = rows > 0 ? matrix[0].size() : 0; std::vector<std::vector<int>> result(cols, std::vector<int>(rows, 0));}

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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++

#include <iostream>
#include <vector>

std::vector<std::vector<int>> transformMatrix(const std::vector<std::vector<int>>& matrix) {
    int rows = matrix.size();
    int cols = rows > 0 ? matrix[0].size() : 0;
    std::vector<std::vector<int>> result(cols, std::vector<int>(rows, 0));

    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            result[j][i] = matrix[i][j];
        }
    }

    return result;
}


int main() {
    // Initial matrix (2D vector)
    std::vector<std::vector<int>> matrix = {
        {1, 2, 3},
        {4, 5, 6}
    };
    
    // Call our function on the matrix and output the result
    std::vector<std::vector<int>> transposed = transformMatrix(matrix);
    for (const auto& row : transposed) {
        for (int elem : row) {
            std::cout << elem << " ";
        }
        std::cout << std::endl;
    }
    return 0;
}

#include <iostream>
#include <vector>

std::vector<std::vector<int>> transformMatrix(const std::vector<std::vector<int>>& matrix) {
    int rows = matrix.size();
    int cols = rows > 0 ? matrix[0].size() : 0;
    std::vector<std::vector<int>> result(cols, std::vector<int>(rows, 0));

    for (int i = 0; i < rows; ++i) {
        for (int j = 0; j < cols; ++j) {
            result[j][i] = matrix[i][j];
        }
    }

    return result;
}


int main() {
    // Initial matrix (2D vector)
    std::vector<std::vector<int>> matrix = {
        {1, 2, 3},
        {4, 5, 6}
    };
    
    // Call our function on the matrix and output the result
    std::vector<std::vector<int>> transposed = transformMatrix(matrix);
    for (const auto& row : transposed) {
        for (int elem : row) {
            std::cout << elem << " ";
        }
        std::cout << std::endl;
    }
    return 0;
}

This step concludes our solution!