{"id":1048,"date":"2024-10-21T15:02:46","date_gmt":"2024-10-21T09:32:46","guid":{"rendered":"https:\/\/codexplained.in\/?p=1048"},"modified":"2025-11-24T15:29:01","modified_gmt":"2025-11-24T09:59:01","slug":"find-sum-of-diagonal-elements-in-a-matrix","status":"publish","type":"post","link":"https:\/\/codexplained.in\/?p=1048","title":{"rendered":"Find Sum of Diagonal Elements in a Matrix"},"content":{"rendered":"\n

Introduction<\/h3>\n\n\n\n

In a square matrix, the diagonal elements are those that extend from the top left corner to the bottom right corner. For example, in a n\u00d7nn \\times nn\u00d7n matrix, the diagonal elements are located at positions (0,0),(1,1),(2,2),\u2026,(n\u22121,n\u22121)(0,0), (1,1), (2,2), \\ldots, (n-1,n-1)(0,0),(1,1),(2,2),\u2026,(n\u22121,n\u22121). The sum of these diagonal elements can be useful in various mathematical applications, including linear algebra and computer graphics.<\/p>\n\n\n

\n#include <stdio.h>\n\n#define MAX 10  \/\/ Maximum size of the matrix\n\nvoid inputMatrix(int matrix[MAX][MAX], int size) {\n    printf("Enter elements of the matrix (%d x %d):\\n", size, size);\n    for (int i = 0; i < size; i++) {\n        for (int j = 0; j < size; j++) {\n            scanf("%d", &matrix[i][j]);\n        }\n    }\n}\n\nint sumDiagonal(int matrix[MAX][MAX], int size) {\n    int sum = 0;\n    for (int i = 0; i < size; i++) {\n        sum += matrix[i][i];  \/\/ Add diagonal elements\n    }\n    return sum;\n}\n\nvoid printMatrix(int matrix[MAX][MAX], int size) {\n    printf("Matrix (%d x %d):\\n", size, size);\n    for (int i = 0; i < size; i++) {\n        for (int j = 0; j < size; j++) {\n            printf("%d ", matrix[i][j]);\n        }\n        printf("\\n");\n    }\n}\n\nint main() {\n    int matrix[MAX][MAX];\n    int size;\n\n    printf("Enter the size of the matrix: ");\n    scanf("%d", &size);\n\n    inputMatrix(matrix, size);\n    \n    printf("Original Matrix:\\n");\n    printMatrix(matrix, size);\n    \n    int diagonalSum = sumDiagonal(matrix, size);\n    printf("Sum of diagonal elements: %d\\n", diagonalSum);\n\n    return 0;\n}\n<\/pre><\/div>\n\n\n
Explanation<\/h3>\n\n\n\n
    \n
  1. Includes and Defines<\/strong>: The program includes the stdio.h<\/code> header for input\/output functions and defines a constant MAX<\/code> for the maximum size of the matrix.<\/li>\n\n\n\n
  2. Input Function<\/strong>: The inputMatrix<\/code> function prompts the user to enter the elements of a square matrix of size size\u00d7sizesize \\times sizesize\u00d7size.<\/li>\n\n\n\n
  3. Sum Function<\/strong>: The sumDiagonal<\/code> function calculates the sum of the diagonal elements by iterating through the matrix and adding the elements located at positions (i,i)(i, i)(i,i).<\/li>\n\n\n\n
  4. Print Function<\/strong>: The printMatrix<\/code> function displays the matrix in a formatted manner.<\/li>\n\n\n\n
  5. Main Function<\/strong>: In main<\/code>, the program:\n
      \n
    • Declares a matrix.<\/li>\n\n\n\n
    • Asks for the size of the matrix.<\/li>\n\n\n\n
    • Calls the input, print, and sum functions to display the results.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
      Input<\/h3>\n\n\n\n
      The user is prompted to enter the size of the matrix, followed by the matrix elements. Example input:<\/p>\n\n\n
      \nEnter the size of the matrix: 3\nEnter elements of the matrix (3 x 3):\n1 2 3\n4 5 6\n7 8 9\n<\/pre><\/div>\n\n\n
      Output<\/h3>\n\n\n\n
      The program will output the original matrix and the sum of its diagonal elements. For the example input, the output will be:<\/p>\n\n\n
      \nOriginal Matrix:\n1 2 3 \n4 5 6 \n7 8 9 \n\nSum of diagonal elements: 15\n<\/pre><\/div>\n\n\n
      Conclusion<\/h3>\n\n\n\n
      This C program effectively demonstrates how to find the sum of the diagonal elements in a square matrix. This operation is fundamental in various mathematical contexts and serves as a useful exercise for understanding matrix manipulation in C. The code can be easily modified to handle different matrix sizes or data types, making it adaptable for various applications.<\/p>\n