// CSCI 1410 Programming assignment 5
// Written by Hanyuan Li <hanyuan.li@ucdenver.edu>
// Elementary cellular automata

#include <iostream>
#include <cstdlib>
using namespace std;

void setup_row();
void print_row();
void update_row();
int find_next_cell_state(int left_neighbor, int cell, int right_neighbor);
int z;

const int WIDTH=80;
int row[WIDTH];

int main()
{
    setup_row();
    print_row();

    for(int i = 0; i < 42; i++)
    {
//       update_row();
        print_row();
    }
}

// The setup_row function creates an initial state for the cellular autonoma
void setup_row()
{
    for(int z = 0; z < 80; z++)
	{
	row[z] = 0;
	row[39] = 1;
	cout << row[z];
	}
	cout << endl;
}

// The print_row function outputs the state of the row to the user.  For all
// cells that are 0, it outputs a space (" "), for all cells that are 1, it
// outputs a star ("*")
void print_row()
{
    if(row[z] == 0)
	{
	    cout << " ";
	}
	else
	{
	    cout << "*";
	}
}

// The update_row function updates the contents of the row after calculating
// the next states using the find_next_cell_state function
void update_row(int left_neighbor, int cell, int right_neighbor)
{
    for(int x = 0; x < 80; x++)
    {
	left_neighbor = row[x];
	cell = row[x+1];
	right_neighbor = row[x+2];
	row[x] = find_next_cell_state(left_neighbor, cell, right_neighbor);
	}
}

// The find_next_cell_state function implements the Rule 30 celular autonoma rules.
// The states for this are:
//
// 111 110 101 100 011 010 001 000
//  0   0   0   1   1   1   1   0

int find_next_cell_state(int left_neighbor, int cell, int right_neighbor)
{
    if (0 == cell)
    {
        if (1 == (left_neighbor + right_neighbor))
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }
    else
    {
        if (1 == left_neighbor)
        {
            return 0;
        }
        else
        {
            return 1;
        }
    }
}