Add Two Matrix in C++

To add two matrices in C++, you’ll need to make sure that they have the same dimensions (i.e., same number of rows and columns). Here’s a C++ program that demonstrates how to add two matrices:

#include <iostream>
#include <vector>

std::vector<std::vector<int>> addMatrices(const std::vector<std::vector<int>>& A, const std::vector<std::vector<int>>& B) {
    int rows = A.size();
    int cols = A[0].size();

    std::vector<std::vector<int>> result(rows, std::vector<int>(cols, 0));

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

    return result;
}

void printMatrix(const std::vector<std::vector<int>>& matrix) {
    for (const auto& row : matrix) {
        for (int element : row) {
            std::cout << element << " ";
        }
        std::cout << std::endl;
    }
}

int main() {
    std::vector<std::vector<int>> A = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    std::vector<std::vector<int>> B = {{9, 8, 7}, {6, 5, 4}, {3, 2, 1}};

    if (A.size() == B.size() && A[0].size() == B[0].size()) {
        std::vector<std::vector<int>> sum = addMatrices(A, B);

        std::cout << "Matrix A:" << std::endl;
        printMatrix(A);

        std::cout << "Matrix B:" << std::endl;
        printMatrix(B);

        std::cout << "Sum of matrices A and B:" << std::endl;
        printMatrix(sum);
    } else {
        std::cout << "Error: Matrices must have the same dimensions for addition." << std::endl;
    }

    return 0;
}

In this program:

• The function addMatrices takes two matrices A and B as input and returns a new matrix that represents their sum.
• It first checks if the dimensions of A and B are compatible for addition.
• It then creates a result matrix with the same dimensions as the input matrices.
• It iterates through each element of A and B, adding the corresponding elements and storing the result in the corresponding position of the result matrix.
• The function printMatrix is used to print a matrix to the console.
• In the main function, two example matrices A and B are defined and then added together. The result is printed to the console.

Make sure that both matrices have the same number of rows and columns for successful addition.