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

#define FINISH 99

void *my_malloc(size_t size)
{
static int finish = 0;
if (finish++ == FINISH)
 return NULL;
return malloc(size);
}
#define malloc my_malloc


void *my_calloc(size_t count, size_t size)
{
static int finish = 0;
if (finish++ == FINISH)
 return NULL;
return calloc(count, size);
}
#define calloc my_calloc


double **alloc(double **tab, int size)
{
    int row1=0,row2=0;
    tab = NULL;
    tab = malloc( size*sizeof(double *));   /*allocating the memory for the first dimension*/
    if (tab == NULL)
    {
        printf("Not enough memory\n");
        free(tab);
        tab=0;
        return 0;
    }
    for (row1=0;row1<size;row1++)
    {
      tab[row1]=malloc(size * sizeof(double));  /*allocating the memory fot the second dimension*/
      if(tab[row1] == NULL)
      {
        printf("Not enough memory\n");
        for (row2=0;row2<=row1;row2++)
            free(tab[row2]);
        free(tab);
        tab=0;
        return 0;
      }
    }
    return tab;
}
double det(double **matrix, int size)
{
    double **minor=NULL;
    double result=0;

    int row,col,chosencol;

    if(size==1)
    {
        result+=matrix[0][0];
        return result;
    }

    else
    {
        for(chosencol=0;chosencol<size;chosencol++)
        {
            minor =alloc(minor,size-1);
            if(minor==NULL)
            {
                free(minor);
                return 0;
            }


            for(row=1;row<size;row++)
            {
                for(col=0;col<chosencol;col++)
                    minor[row-1][col]=matrix[row][col];
                for(col=chosencol+1;col<size;col++)
                    minor[row-1][col-1]=matrix[row][col];
            }
            result+=pow((int)-1,(int)(2+chosencol))*  matrix[0][chosencol]* det(minor,size-1);

            for(row=0;row<size-1;row++)
                free(minor[row]);
            free(minor);
        }
    }
    return result;
}

int main()
{
    int row,col;
    int size=0;
    char temp[10];
    double **matrix;


    while(size==0)
    {
        printf("\nPlease enter the size of square matrix,\nfor which determinant is to be calculated: ");
        fgets (temp,10, stdin);
        size=(int)strtod(temp,NULL);
    }

    matrix=alloc(matrix,size);

    printf("\nPlease give the values of %d-dimnesioned matrix:\n",size);
    for(row=0; row<size; row++)
        for(col=0; col<size; col++)
        {

            {
                printf("the %d. %d. element: ",row+1,col+1);
                fgets (temp,10, stdin);
                matrix[row][col]=(double)strtod(temp,NULL);
            }
        }

    printf("\nYour matrix:\n");
    for(row=0;row<size;row++)
    {
        for(col=0;col<size;col++)
            printf("%g\t",*(*(matrix+row)+col));
        printf("\n");
    }

    printf("\nDeterminant: %g\n", det(matrix,size));
    for(row=0;row<size;row++)
        free(matrix[row]);
    free(matrix);
    getchar();
    return(0);
}