Example: Matrix Multiplication in C++

// Matrix Multiplication
#include <iostream>
#include <vector> // Required for std::vector

int main() {
    // Step 1: Define matrix dimensions
    const int R1 = 2; // Rows of Matrix A
    const int C1 = 3; // Columns of Matrix A (also Rows of Matrix B)
    const int R2 = 3; // Rows of Matrix B
    const int C2 = 2; // Columns of Matrix B

    // Check if multiplication is possible
    if (C1 != R2) {
        std::cout << "Error: Number of columns in Matrix A must be equal to number of rows in Matrix B." << std::endl;
        return 1; // Indicate an error
    }

    // Step 2: Initialize matrices A and B
    std::vector<std::vector<int>> matrixA = {
        {1, 2, 3},
        {4, 5, 6}
    };

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

    // Step 3: Initialize result matrix C with zeros
    // C will have dimensions R1 x C2
    std::vector<std::vector<int>> resultMatrixC(R1, std::vector<int>(C2, 0));

    // Step 4: Perform matrix multiplication
    // Outer loop for rows of resultMatrixC (corresponds to rows of matrixA)
    for (int i = 0; i < R1; ++i) {
        // Middle loop for columns of resultMatrixC (corresponds to columns of matrixB)
        for (int j = 0; j < C2; ++j) {
            // Inner loop for sum of products (corresponds to columns of matrixA / rows of matrixB)
            for (int k = 0; k < C1; ++k) {
                resultMatrixC[i][j] += matrixA[i][k] * matrixB[k][j];
            }
        }
    }

    // Step 5: Print the result matrix C
    std::cout << "Resultant Matrix C (" << R1 << "x" << C2 << "):" << std::endl;
    for (int i = 0; i < R1; ++i) {
        for (int j = 0; j < C2; ++j) {
            std::cout << resultMatrixC[i][j] << " ";
        }
        std::cout << std::endl;
    }

    return 0;
}