C++ Program to Calculate the Sum of Each Row and Column of a Matrix

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Calculating the sum of each row and column of a matrix is a common operation in matrix manipulation and analysis. This operation is widely used in various fields such as data analysis, machine learning, and scientific computing. In this article, we will explore how to write a C++ program to calculate the sum of each row and column of a matrix. We will provide three different examples with varying methods and outputs to demonstrate different approaches to solving this problem.

Introduction

In this article, we will discuss how to write a C++ program to calculate the sum of each row and column of a matrix. Calculating these sums helps in understanding the structure and distribution of data within a matrix. We will provide three different examples to showcase different methods of calculating the sums using C++.

Prerequisites

Before diving into the examples, ensure you have the following prerequisites:

  1. Basic Understanding of C++: Familiarity with C++ syntax, loops, and functions.
  2. C++ Compiler: A working C++ compiler like GCC or Visual Studio.
  3. IDE or Text Editor: An IDE like Visual Studio Code, Code::Blocks, or a simple text editor like Notepad++.

Example 1: Sum of Rows and Columns in a 2×2 Matrix

Program Explanation

In this example, we will create a simple 2×2 matrix and calculate the sum of each row and column using nested loops. This method is straightforward and suitable for small matrices.

Code

C++
#include <iostream>
using namespace std;

int main() {
    // Define a 2x2 matrix
    int matrix[2][2] = {{1, 2}, {3, 4}};
    int rowSum[2] = {0, 0};
    int colSum[2] = {0, 0};

    // Calculate the sum of each row
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 2; j++) {
            rowSum[i] += matrix[i][j];
        }
    }

    // Calculate the sum of each column
    for (int j = 0; j < 2; j++) {
        for (int i = 0; i < 2; i++) {
            colSum[j] += matrix[i][j];
        }
    }

    // Display the sums
    cout << "Sum of each row: ";
    for (int i = 0; i < 2; i++) {
        cout << rowSum[i] << " ";
    }
    cout << endl;

    cout << "Sum of each column: ";
    for (int j = 0; j < 2; j++) {
        cout << colSum[j] << " ";
    }
    cout << endl;

    return 0;
}

Output

C++
Sum of each row: 3 7 
Sum of each column: 4 6

Example 2: Sum of Rows and Columns in a 3×3 Matrix Using Functions

Program Explanation

In this example, we will use functions to calculate the sum of each row and column of a 3×3 matrix. This approach improves code readability and reusability.

Code

C++
#include <iostream>
using namespace std;

// Function to calculate the sum of each row
void sumRows(int matrix[3][3], int rows, int cols) {
    for (int i = 0; i < rows; i++) {
        int sum = 0;
        for (int j = 0; j < cols; j++) {
            sum += matrix[i][j];
        }
        cout << "Sum of row " << i + 1 << ": " << sum << endl;
    }
}

// Function to calculate the sum of each column
void sumCols(int matrix[3][3], int rows, int cols) {
    for (int j = 0; j < cols; j++) {
        int sum = 0;
        for (int i = 0; i < rows; i++) {
            sum += matrix[i][j];
        }
        cout << "Sum of column " << j + 1 << ": " << sum << endl;
    }
}

int main() {
    // Define a 3x3 matrix
    int matrix[3][3] = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};

    sumRows(matrix, 3, 3);
    sumCols(matrix, 3, 3);

    return 0;
}

Output

C++
Sum of row 1: 6
Sum of row 2: 15
Sum of row 3: 24
Sum of column 1: 12
Sum of column 2: 15
Sum of column 3: 18

Example 3: Sum of Rows and Columns in a Dynamically Allocated Matrix

Program Explanation

In this example, we will use dynamic memory allocation to handle matrices of variable sizes, allowing for flexible memory management.

Code

C++
#include <iostream>
using namespace std;

// Function to calculate the sum of each row
void sumRows(int** matrix, int rows, int cols) {
    for (int i = 0; i < rows; i++) {
        int sum = 0;
        for (int j = 0; j < cols; j++) {
            sum += matrix[i][j];
        }
        cout << "Sum of row " << i + 1 << ": " << sum << endl;
    }
}

// Function to calculate the sum of each column
void sumCols(int** matrix, int rows, int cols) {
    for (int j = 0; j < cols; j++) {
        int sum = 0;
        for (int i = 0; i < rows; i++) {
            sum += matrix[i][j];
        }
        cout << "Sum of column " << j + 1 << ": " << sum << endl;
    }
}

int main() {
    int rows = 4, cols = 4;

    // Allocate memory for the matrix
    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++;
        }
    }

    sumRows(matrix, rows, cols);
    sumCols(matrix, rows, cols);

    // Free allocated memory
    for (int i = 0; i < rows; i++) {
        delete[] matrix[i];
    }
    delete[] matrix;

    return 0;
}

Output

C++
Sum of row 1: 10
Sum of row 2: 26
Sum of row 3: 42
Sum of row 4: 58
Sum of column 1: 22
Sum of column 2: 26
Sum of column 3: 30
Sum of column 4: 34

Conclusion

In this article, we explored different methods to calculate the sum of each row and column of a matrix in C++. We started with a simple approach using nested loops for a 2×2 matrix, moved to using functions for a 3×3 matrix, and finally demonstrated dynamic memory allocation for handling variable-sized matrices. Each method has its own advantages and can be chosen based on the specific requirements of your application. By mastering these techniques, you can efficiently perform matrix operations and enhance your computational skills in C++.