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

#define FROM -10.0
#define TO    10.0
#define STEP   0.01

#define sigmoid_slope -1.0

typedef struct {
    double output;
    double thres;
    double inp_wgt;
} neuron;


void initialize_neuron(neuron *x)
{
	x->thres = 0.0;
	x->inp_wgt = 1.0;
	x->output = 0.0;
}

double sigmoid(double value)
{
    return 1.0 / ( 1.0 + exp(sigmoid_slope * value) );
}

void update_neuron(neuron *x, double input)
{
	x->output = sigmoid(x->inp_wgt * input - x->thres);
}

int main(int argc, char **argv)
{
	neuron a;
	double x;

  initialize_neuron(&a);

	x = FROM;
	while ( x <= TO ){
		update_neuron(&a, x);
		printf("%f %f\n", x, a.output);
		x += STEP;
	}
	return EXIT_SUCCESS;
}