Matrix is a sparse matrix or not

Posted on Apr 26, 2020

C program to check whether a two dimensional array is a sparse matrix.

Any matrix is called a sparse matrix if most of its elements are zero. If the number of zeros (T) in a matrix exceeds (n*m)/2, where n, m is the dimension of the matrix, matrix is sparse matrix. Sparse matrix has more zero elements than nonzero elements.
T >= (n*m)/2

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 sparse(int mat[MAX][MAX], int row, int col)
{
    int i, j, count;

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

    if(count >= (row*col)/2)
    {
        printf("\nMatrix is a sparse matrix");
    }
    else
    {
        printf("\nMatrix is not a sparse matrix");
    }
}

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

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

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

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

    sparse(mat, row, col);

    getch();
}

Output

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

Enter the number of rows of the matrix  :3
Enter the number of columns of the matrix       :4
Enter the elements of the matrix
Element [0][0]  :1
Element [0][1]  :2
Element [0][2]  :0
Element [0][3]  :0
Element [1][0]  :0
Element [1][1]  :3
Element [1][2]  :4
Element [1][3]  :0
Element [2][0]  :0
Element [2][1]  :5
Element [2][2]  :0
Element [2][3]  :0

Matrix entered is
1       2       0       0
0       3       4       0
0       5       0       0

Matrix is a sparse matrix


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

Enter the number of rows of the matrix  :3
Enter the number of columns of the matrix       :4
Enter the elements of the matrix
Element [0][0]  :1
Element [0][1]  :2
Element [0][2]  :3
Element [0][3]  :4
Element [1][0]  :5
Element [1][1]  :0
Element [1][2]  :0
Element [1][3]  :0
Element [2][0]  :6
Element [2][1]  :5
Element [2][2]  :6
Element [2][3]  :0

Matrix entered is
1       2       3       4
5       0       0       0
6       5       6       0

Matrix is not a sparse matrix