Multi-Dimensional Arrays in C++

A multi-dimensional array is an array that contains other arrays. It's a fundamental data structure in C++ used to represent tables, matrices, and other structured data. In this guide, we'll explore multi-dimensional arrays in C++ and provide sample code to illustrate their usage.

Two-Dimensional Arrays

A two-dimensional array is a matrix-like structure with rows and columns. It is often used to represent grids of data. Here's an example:

#include <iostream>
using namespace std;
int main() {
    int matrix[3][3] = {
        {1, 2, 3},
        {4, 5, 6},
        {7, 8, 9}
    };
    cout << "Two-Dimensional Array (Matrix):" << endl;
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}
    

In this example, we declare a 3x3 two-dimensional array to represent a matrix and initialize it with values. We then use nested loops to iterate through the rows and columns and print the matrix.

Three-Dimensional Arrays

A three-dimensional array extends the concept to three dimensions and is often used for 3D data structures. Here's an example:

#include <iostream>
using namespace std;
int main() {
    int cube[2][2][3] = {
        {{1, 2, 3}, {4, 5, 6}},
        {{7, 8, 9}, {10, 11, 12}}
    };
    cout << "Three-Dimensional Array (Cube):" << endl;
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 2; j++) {
            for (int k = 0; k < 3; k++) {
                cout << cube[i][j][k] << " ";
            }
            cout << "  ";
        }
        cout << endl;
    }
    return 0;
}
    

In this example, we declare a 2x2x3 three-dimensional array to represent a cube and initialize it with values. We use nested loops to iterate through the three dimensions and print the cube.

Multi-Dimensional Arrays with Pointers

Multi-dimensional arrays can also be represented using pointers. Here's an example of a two-dimensional array with pointers:

#include <iostream>
using namespace std;
int main() {
    int rows = 3;
    int cols = 4;
    int** matrix = new int*[rows];
    for (int i = 0; i < rows; i++) {
        matrix[i] = new int[cols];
    }
    // Initialize the matrix
    int value = 1;
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = value;
            value++;
        }
    }
    cout << "Two-Dimensional Array (Pointers):" << endl;
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
    // Deallocate memory
    for (int i = 0; i < rows; i++) {
        delete[] matrix[i];
    }
    delete[] matrix;
    return 0;
}
    

In this example, we use dynamic memory allocation to create a two-dimensional array using pointers. We initialize and print the array and then deallocate the memory to avoid memory leaks.

Conclusion

Multi-dimensional arrays in C++ are versatile data structures that allow you to work with structured data in a grid or cube-like format. Whether you're representing a table of values or 3D structures, understanding multi-dimensional arrays is crucial for various applications in C++ programming.