Example: Matrix Multiplication in C++

// Matrix Multiplication
#include <iostream>
#include <vector> // Using vector for dynamic arrays, better practice than raw arrays

// Function to print a matrix
void printMatrix(const std::vector<std::vector<int>>& matrix) {
    for (const auto& row : matrix) {
        for (int val : row) {
            std::cout << val << "\t";
        }
        std::cout << std::endl;
    }
}

int main() {
    // Define matrices A and B
    std::vector<std::vector<int>> matrixA = {
        {1, 2, 3},
        {4, 5, 6}
    }; // 2x3 matrix

    std::vector<std::vector<int>> matrixB = {
        {7, 8},
        {9, 1},
        {2, 3}
    }; // 3x2 matrix

    // Get dimensions of matrices
    int rowA = matrixA.size();
    int colA = matrixA[0].size();
    int rowB = matrixB.size();
    int colB = matrixB[0].size();

    // Step 1: Check if multiplication is possible
    if (colA != rowB) {
        std::cout << "Error: Number of columns in Matrix A must be equal to number of rows in Matrix B." << std::endl;
        return 1; // Indicate error
    }

    // Step 2: Initialize result matrix C with appropriate dimensions (rowA x colB)
    std::vector<std::vector<int>> matrixC(rowA, std::vector<int>(colB, 0));

    // Step 3: Perform matrix multiplication
    // Outer loop iterates through rows of matrixA (i)
    for (int i = 0; i < rowA; ++i) {
        // Middle loop iterates through columns of matrixB (j)
        for (int j = 0; j < colB; ++j) {
            // Inner loop calculates the dot product of row i of matrixA and column j of matrixB
            for (int k = 0; k < colA; ++k) { // colA can also be rowB, since they are equal
                matrixC[i][j] += matrixA[i][k] * matrixB[k][j];
            }
        }
    }

    // Step 4: Print the matrices and their product
    std::cout << "Matrix A (" << rowA << "x" << colA << "):" << std::endl;
    printMatrix(matrixA);

    std::cout << "\nMatrix B (" << rowB << "x" << colB << "):" << std::endl;
    printMatrix(matrixB);

    std::cout << "\nResultant Matrix C (" << rowA << "x" << colB << "):" << std::endl;
    printMatrix(matrixC);

    return 0;
}