Square matrix is symmetric or not

Posted on Apr 26, 2020

C program to check whether given square matrix is symmetric or not.

A square matrix is called symmetric matrix if that matrix is equal to its transposed matrix. A symmetric matrix is always a square matrix. Symmetric matrix A is defined as: A = A^T

Program

#include<stdio.h>
#include<conio.h>
#define MAX 10

void read_matrix(int mat[MAX][MAX], int row, int col)
{
    int i, j;
    for(i=0;i<row;i++)
    {
        for(j=0;j<col;j++)
        {
            printf("Element [%d][%d]\t:",i,j);
            scanf("%d",&mat[i][j]);
        }
    }
}

void print_matrix(int mat[MAX][MAX], int row, int col)
{
    int i, j;
    for(i=0;i<row;i++)
    {
        for(j=0;j<col;j++)
        {
            printf("%d\t",mat[i][j]);
        }
        printf("\n");
    }
}

void symmetric(int mat[MAX][MAX], int row)
{
    int i, j, trans[MAX][MAX], flag;

    for(i=0;i<row;i++)
    {
        for(j=0;j<row;j++)
        {
            trans[j][i] = mat[i][j];
        }
    }

    flag = 0;
    for(i=0;i<row;i++)
    {
        for(j=0;j<row;j++)
        {
            if(mat[i][j] != trans[i][j])
            {
                flag = 1;
                break;
            }
        }
    }

    if(flag == 0)
    {
        printf("\nMatrix is symmetric matrix");
    }
    else
    {
        printf("\nMatrix is not a symmetric matrix");
    }
}

void main()
{
    int mat[MAX][MAX];
    int row, col;

    printf("Enter the number of rows or columns of the square matrix\t:");
    scanf("%d",&row);
    col = row;

    printf("Enter the elements of the matrix\n");
    read_matrix(mat, row, col);

    printf("\nMatrix entered is\n");
    print_matrix(mat, row, col);

    symmetric(mat, row);

    getch();
}

Output

********** Run1 ********** 

Enter the number of rows or columns of the square matrix        :4
Enter the elements of the matrix
Element [0][0]  :9
Element [0][1]  :13
Element [0][2]  :3
Element [0][3]  :6
Element [1][0]  :13
Element [1][1]  :11
Element [1][2]  :7
Element [1][3]  :6
Element [2][0]  :3
Element [2][1]  :7
Element [2][2]  :4
Element [2][3]  :7
Element [3][0]  :6
Element [3][1]  :6
Element [3][2]  :7
Element [3][3]  :10

Matrix entered is
9       13      3       6
13      11      7       6
3       7       4       7
6       6       7       10

Matrix is symmetric matrix


********** Run2 ********** 

Enter the number of rows or columns of the square matrix        :3
Enter the elements of the matrix
Element [0][0]  :1
Element [0][1]  :2
Element [0][2]  :3
Element [1][0]  :4
Element [1][1]  :5
Element [1][2]  :6
Element [2][0]  :7
Element [2][1]  :8
Element [2][2]  :9

Matrix entered is
1       2       3
4       5       6
7       8       9

Matrix is not a symmetric matrix