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

double determinant(double **array_one, int matrixSize);        /*Recursive determinant function*/
double **allocMemory(int matrixSize);                /*Function that allocates memory*/
void readkeys(double **array_one, int matrixSize);        /*Read numbers into matrix from the keyboard*/
int readMatrixSize();                        /*Reads matrix size*/
int main()
{
    int matrixSize;
    int vertical, horizontal;                /*Vertical and horizontal location in dynamic allocated array*/
    double **array_one=NULL;/**/
    matrixSize=readMatrixSize();
    array_one=allocMemory(matrixSize);            /*Returning pointer from function*/
    readkeys(array_one, matrixSize);
    for(vertical=0; vertical<matrixSize; vertical++)    /*Showing filled array, for test purposes*/
    {
        printf("\n");
        for(horizontal=0; horizontal<matrixSize; horizontal++)
            printf("%-5f ", array_one[vertical][horizontal]);
    }
    printf("\n\nDeterminant=%f\n", determinant(array_one, matrixSize));    /*Calculation of determinant*/
    for(vertical=0; vertical<matrixSize; vertical++)
    {
        free(array_one[vertical]);                    /*Freeing allocated memory of second dimension*/
    }
    free(array_one);                                /*Freeing first dimension*/

    return 0;
}

void readkeys(double **array_one, int matrixSize)
{
    int trash=0;
    int check=0;                        /*If one you've inputed good valude */
    int vertical;
    int horizontal;
    for(vertical=0; vertical<matrixSize; vertical++)
        for(horizontal=0; horizontal<matrixSize; horizontal++)
        {
            check=0;
            printf("Number: ");
            while(check==0 || trash!='\n')
            {
                check=scanf("%lf", &array_one[vertical][horizontal]);
                trash=getchar();
                if(check==0 ||trash!='\n' )
                {
                    printf("Wrong number!!!!!\n");
                }
                __fpurge(stdin);
            }
        }

}

int readMatrixSize()
{
    int trash=0;
    int matrixSize;
    int check=0;                            /*If one you've inputed good valude */
    while(check==0 || matrixSize<1 ||trash!='\n')                            /*Checking correctness of input value*/
    {
        check=scanf("%d", &matrixSize);
        trash=getchar();
        if(check==0 || matrixSize<1 ||trash!='\n' )
        {
            printf("Wrong number!!!!!\n");
        }
        __fpurge(stdin);
    }
    printf("Size of matrix: %d\n", matrixSize);
    return matrixSize;

}

double **allocMemory(int matrixSize)
{
    int vertical;
    double **new_one=NULL;
    new_one = malloc(matrixSize*sizeof(double *));
    if (new_one == 0)
    {
        printf("ERROR: Out of memory\n");
        free(new_one);
        exit(1);
    }
    for(vertical=0; vertical<matrixSize; vertical++)
    {
        new_one[vertical] = malloc(matrixSize*sizeof(double));
        if (new_one[vertical] == 0)
        {
            printf("ERROR: Out of memory another dimension\n");
            while(vertical>0)
            {
                vertical--;
                free(new_one[vertical]);
            }
            free(new_one);
            exit(1);
        }
    }
    return new_one;
}

double determinant(double **array_one, int matrixSize)
{
    double determinantV=0;
    int multiplier;
    int vertical, horizontal;
    int newVertical, newHorizontal;
    double **minor_one=NULL;
    if (matrixSize==1)
        return array_one[0][0];
    if (matrixSize==2)
        return array_one[0][0]*array_one[1][1]-array_one[0][1]*array_one[1][0];      /*Formula to calculate matrix of size 2*/
    matrixSize=matrixSize-1;                                /*Changing size of matrix*/
    minor_one=allocMemory(matrixSize);
    for(multiplier=0; multiplier<=matrixSize; multiplier++)
    {
        newHorizontal=0;                                  /*Passing values from major array to minor one*/
        newVertical=0;
        for(horizontal=1; horizontal<=matrixSize; horizontal++)
        {
            for(vertical=0; vertical<=matrixSize; vertical++)
            {
                if(vertical!=multiplier)
                {
                    minor_one[newVertical][newHorizontal]=array_one[vertical][horizontal];
                    newVertical++;
                }
            }
            newVertical=0;
            newHorizontal++;
        }

        if(multiplier%2==0)                                    /*According to formula the component must be multiplied by 1 or -1*/
            determinantV+=array_one[multiplier][0]*determinant(minor_one, matrixSize);
        if(multiplier%2==1)
            determinantV+=(-1)*array_one[multiplier][0]*determinant(minor_one, matrixSize);
    }
    for(vertical=0; vertical<matrixSize; vertical++)                            /*Freeing memory of minor array*/
    {
        free(minor_one[vertical]);
    }
    free(minor_one);
    return determinantV;
}