#include <stdlib.h>
#include <stdio.h>


void free_mat(int rows, double **mat)
{
    int i;
	for(i=0;i<rows;i++)
	{
		free(mat[i]);
	}
	free(mat);
}

int scan_rows(FILE *fp)
{
    int rows;
    fseek(fp,0,SEEK_SET);
    fscanf(fp, "%d", &rows);
    return rows;
}

double **allocate_mem(int rows)
{
 	double **mat=NULL;
	int cols=rows;
	int i;

	mat=(double**)malloc(rows*sizeof(double*));

	for(i=0;i<rows;i++)
	{
		mat[i]=(double*)malloc(cols*sizeof(double));
	}

	return mat;
}

FILE *file_open(char *file_name)
{
    FILE *fp;
    if( (fp=fopen(file_name,"r"))==NULL)
	{
 	 	 printf("Blad otwarcia pliku!\n");}

    return fp;
}

double **load_mat(FILE *fp, int rows)
{
    int i,j;
	int columns=rows;

    double **mat = allocate_mem(rows);

    for(i = 0; i < rows; i++)
	{
        for(j = 0; j < columns; j++)
        {
            fscanf(fp, "%lf", *(mat+i)+j);
            printf("%.2f\t", *(*(mat+i)+j));
        }
	printf("\n");
	}
    return mat;
}

void file_close(FILE *fp)
{
    if(fclose(fp))  printf("Blad zamkniecia pliku\n");
    else    printf("Udalo sie zamknac plik\n");
}
double det(double **mat, int rows)
{
    double **minor = NULL;
    double sum=0;
    double sign=1;
    int i, minor_i, minor_j, mat_i, mat_j;

    if(rows == 1)
    {
        sum = mat[0][0];
        return sum;
    }
    if(rows == 2)
    {
        sum = mat[0][0] * mat[1][1] - mat[1][0] * mat[0][1];
        return sum;
    }

    minor = allocate_mem(rows - 1);
    for(i=0; i < rows; i++)
    {
        for(minor_i=0, mat_i=1; mat_i < rows; mat_i++, minor_i++)
        {
            for(mat_j=0,minor_j=0;minor_j<rows-1;minor_j++,mat_j++)
            {
                if(mat_j == i) mat_j++;
                minor[minor_i][minor_j] = mat[mat_i][mat_j];
               // printf("%.2f\t",minor[minor_i][minor_j]);
            }
           // printf("\n");
        }
       // printf("\n\n");
        sum += sign * mat[0][i] * det(minor, rows-1);
        sign = -sign;
    }
    return sum;
}

int main()
{
    char name[20] = "file_matrix.txt";
	char *file_name = name;

    FILE *fp;
    fp = file_open(file_name);

    double **mat = NULL;
    mat = load_mat(fp, scan_rows(fp));

    printf("\n\nDet= %.2f\n",det(mat, scan_rows(fp)));
    free_mat(scan_rows(fp),mat);
    file_close(fp);


    return 0;
}