game_of_life.cpp

#include <iostream>
using namespace std;
int main() {
	int count = 0, foo = 0, i = 0, j = 0, m = 0, n = 0;
	const int LEN = 10;
	int a[LEN][LEN];
	int b[LEN][LEN];

	for (i = 0; i < LEN; i++) {
		for (j = 0; j < LEN; j++) {
			a[i][j] = b[i][j] = 0;
		}
	}
	// glider
	a[0][1] = 1;
	a[1][2] = 1;
	a[2][2] = 1;
	a[2][1] = 1;
	a[2][0] = 1;

	while (true) {

		// output
		for (i = 0; i < LEN; i++) {
			for (j = 0; j < LEN; j++) {
				cout << a[i][j] << ' ';
			}
			cout << endl;
		}

		cin.ignore(); // allows to press 'enter' to see next step
		system("cls");

		for (i = 0; i < LEN; i++) {
			for (j = 0; j < LEN; j++) {

				// count live neighbors
				count = 0;
				for (m = i - 1; m <= i + 1; m++) {
					for (n = j - 1; n <= j + 1; n++) {
						// make sure to only check within legal range
						if (m >= 0 && n >= 0 && m < LEN 
								   && n < LEN && a[m][n] == 1) {
							count++;
						}
					}
				}

				// apply the rules and put result in b
				b[i][j] = 0;
				if (a[i][j] == 1) {
					count -= 1;
					if ((count == 2) || (count == 3)) {
						b[i][j] = 1;
					}
				} else if (count == 3) {
					b[i][j] = 1;
				}
			}
		}

		// replace a with b, and fill b with zeroes
		for (i = 0; i < LEN; i++) {
			for (j = 0; j < LEN; j++) {
				a[i][j] = b[i][j];
			}
		}

	}
	return 0;
}