Explanation
The program calculates and prints the trace (sum of the main diagonal) and the sum of the secondary diagonal of a square matrix entered by the user.
Header
The code begins with including the standard input-output header file using #include <stdio.h>
.
Variable Declaration
The main()
function is defined, and several variables are declared:
int d
: Stores the size of the matrix (number of rows and columns).int e[d][d]
: Declares a 2D array withd
rows andd
columns to hold the matrix values.int sum1 = 0
: Initializes a variable to store the sum of the main diagonal.int sum2 = 0
: Initializes a variable to store the sum of the secondary diagonal.
Program Description
The program prints a description message for the user to understand its functionality.
User Input
The user is prompted to enter the size of the matrix and its elements:
printf("Enter the matrix size: ");
: Prompts the user to enter the size of the matrix.scanf("%d", &d);
: Reads the size of the matrix and stores it ind
.int e[d][d];
: Declares a 2D array withd
rows andd
columns.printf("Enter the elements of the matrix:\n");
: Prompts the user to enter the elements of the matrix.for (int m = 0; m < d; m++)
: Outer loop to iterate over each row.for (int j = 0; j < d; j++)
: Inner loop to iterate over each column.scanf("%d", &e[m][j]);
: Reads each element of the matrix and stores it in the array.
Diagonal Sums Calculation
The program calculates the sums of the main and secondary diagonals:
for (int o = 0; o < d; o++)
: Loop to iterate over each row (and column for a square matrix).sum1 += e[o][o];
: Adds the elements of the main diagonal (from top-left to bottom-right).sum2 += e[o][d - o - 1];
: Adds the elements of the secondary diagonal (from top-right to bottom-left).
Output Result
The program prints the sums of the main and secondary diagonals:
printf("Sum of main diagonal: %d\n", sum1);
: Prints the sum of the main diagonal.printf("Sum of secondary diagonal: %d\n", sum2);
: Prints the sum of the secondary diagonal.
Program End
The program ends with return 0;
to indicate successful execution.
Code
/*
* -----------------------------------------------------------
* Logic Building with Computer Programming (CSU1128)
* Instructor: Dr. Pankaj Vaidya | Author: Divya Mohan
*
* This code is a part of the educational initiative by dmj.one
* with aim of empowering and inspiring learners in the field of
* Computer Science and Engineering through the respective courses.
*
* (c) 2022, Divya Mohan for dmj.one. All rights reserved.
* -----------------------------------------------------------
*/
#include <stdio.h>
int main()
{
printf("\n\n Program to find the trace of a matrix or sum of diagonals of a matrix entered by the user. Example: 2 2 : |1 2 3 4| i.e. diagnonal1 = 1 + 4 = 5 \n\n");
// Read the matrix size from the user
printf("Enter the matrix size: ");
int d;
scanf("%d", &d);
// Declare a 2D array with d rows and d columns
int e[d][d];
// Read the elements of the matrix from the user
printf("Enter the elements of the matrix:\n");
for (int m = 0; m < d; m++)
{
for (int j = 0; j < d; j++)
{
scanf("%d", &e[m][j]);
}
}
// Initialize the sums of the diagonals
int sum1 = 0; // Sum of main diagonal
int sum2 = 0; // Sum of secondary diagonal
// Calculate the sums of the diagonals
for (int o = 0; o < d; o++)
{
sum1 += e[o][o]; // Main diagonal
sum2 += e[o][d - o - 1]; // Secondary diagonal
}
// Print the results
printf("Sum of main diagonal: %d\n", sum1);
printf("Sum of secondary diagonal: %d\n", sum2);
return 0;
}
Output
Program to find the trace of a matrix or sum of diagonals of a matrix entered by the user. Example: 2 2 : |1 2 3 4| i.e. diagnonal1 = 1 + 4 = 5
Enter the matrix size: 2 2
Enter the elements of the matrix:
4 3 2 6
Sum of main diagonal: 4
Sum of secondary diagonal: 7