void functionB(double **& A, double*& B, int n, double **& U, double **& L)
{
	//wiersz 1. U
	for (int j = 1; j <= n; j++)
		U[1][j] = A[1][j];

	//kolumna 1. L
	if (U[1][1] ==0)
		throw -1;
	else{
		for (int j = 2; j <= n; j++)
			L[j][1] = A[j][1] / U[1][1];
	}
	//i>1
	for (int i = 2; i <= n; i++){
		double sumU = 0;
		double sumL = 0;
		for (int j = i; j <= n; j++){		//U
			sumU = 0;
			for (int k = 1; k <= i - 1; k++)
				sumU += L[i][k] * U[k][j];
			U[i][j] = A[i][j] - sumU;
		}
		for (int j = i + 1; j <= n; j++){	//L
			sumL = 0;
			for (int k = 1; k <= i - 1; k++)
				sumL += L[j][k] * U[k][i];
			if (U[i][i] == 0)				//sprawdzenie 
				throw - 1;
			else
			L[j][i] = (A[j][i] - sumL) / U[i][i];
		}
	}
}