Thread: "Game of Life" help

For my programming class, I have to recreate the "Game of Life" game. Right now, we are only building the foundation for it so it doesn't have to do as much as the real game quite yet. The program should ask the user for input: number of columns, number of rows, seed number for the random gen, birth high, birth low, deathHigh and deathLow. There should be a grid of -'s with random #'s on it to represent the grid (we are going to use graphics later) and each # represents a living cell. The rules are:
1.Any live cell with fewer than deathLow live neighbours dies, as if caused by underpopulation.
2.Any live cell with more than deathHigh live neighbours dies, as if by overcrowding.
3.Any live cell with a number of live neighbours between deathLow and deathHigh lives on to the next generation.
4.Any dead cell with a number of live neighbours between birthLow and birthHigh becomes a live cell.

The "seed" input is to help test the program. If the seed if always the same, then the random gen will always be the same. We have to print out 5 generations. My program works. No errors and it compiles fine. But, my teacher gave us a sample output and mine does not match hers. There is an error somewhere in my alterMatrix method, but I can't find where. Can you guys find it? Thanks a lot.

import java.util.Random; import java.util.Scanner;     //This program creates a board of -'s with random #'s on it. public class Life { // This method asks for user input and calls the initializing and printing // methods public static void main(String[] args) {   Scanner console = new Scanner(System.in); // Creates new scanner System.out.println("Number of rows?"); int rows = console.nextInt(); // Stores user input as number of rows   System.out.println("Number of columns?"); int columns = console.nextInt(); // Stores user input as number of // columns   System.out.println("Seed number?"); long seed = console.nextLong(); // Stores user input as number of seed   System.out.println("Birth minimum?"); int birthLow = console.nextInt(); // Store user input as the minimum // number for birth   System.out.println("Birth maximum?"); int birthHigh = console.nextInt(); // Stores user input as maximum // number for birth   System.out.println("Live minimum?"); int liveLow = console.nextInt(); // Stores user input as minimum for // death   System.out.println("Live maximum?"); int liveHigh = console.nextInt(); // stores user input as maximum for // death   boolean initMatrix[][] = new boolean[rows][columns]; // creates new // boolean array // sized // according to // user input   array(initMatrix, rows, columns, seed); // calls the initializing method   printArray(initMatrix, rows, columns); // calls the printing method   System.out.println();   for(int i=0; i<4; i++){  	alterMatrix(initMatrix, rows, columns, birthLow, birthHigh, liveLow, liveHigh);	printArray(initMatrix, rows, columns);	System.out.println(); }   }   // This method initializes the array with trues and falses public static void array(boolean[][] Matrix, int rows, int columns, long seed) {   Random generator = new Random(seed); // creates random number according // to user seed   // loop goes through every row starting at 2nd and ending at 2nd to last for (int i = 1; i < rows - 1; i++) { // loop goes through every column starting at 2nd and ending at 2nd // to last for (int j = 1; j < columns - 1; j++) {   // generates random value boolean x = generator.nextBoolean();   // if x is false, set that array spot as false if (!x) { Matrix[i][j] = false;   }   // if x is true, set that array spot as true else { Matrix[i][j] = true; } } } }   // This method prints the array public static void printArray(boolean[][] Matrix, int rows, int columns) {   // these loops go through every value in the array for (int k = 0; k < rows; k++) { for (int m = 0; m < columns; m++) {   // if the array is false, print a - if (!Matrix[k][m]) { System.out.print("- "); }   // if the array is true, print a # else { System.out.print("# "); } } System.out.println(); // starts a new row } }   public static void alterMatrix(boolean[][] initialMatrix, int rows, int columns, int birthLow, int birthHigh, int liveLow, int liveHigh) {   boolean matrixUpdate[][] = initialMatrix.clone(); for (int row = 0; row < initialMatrix.length; row++) { matrixUpdate[row] = matrixUpdate[row].clone();   // loop goes through every row starting at 2nd and ending at 2nd to // last for (int i = 1; i < rows - 1; i++) { // loop goes through every column starting at 2nd and ending at // 2nd // to last for (int j = 1; j < columns - 1; j++) {   // if initMatrix was false, look to see if life can be born if (!initialMatrix[i][j]) { int counter = 0; // These if statements test each neighboring spot for // life // if life is there, counter will increase by 1 if (initialMatrix[i - 1][j - 1] == true) { counter = counter + 1; } if (initialMatrix[i - 1][j] == true) { counter = counter + 1; } if (initialMatrix[i - 1][j + 1] == true) { counter = counter + 1; } if (initialMatrix[i][j - 1] == true) { counter = counter + 1; } if (initialMatrix[i][j + 1] == true) { counter = counter + 1; } if (initialMatrix[i + 1][j + 1] == true) { counter = counter + 1; } if (initialMatrix[i + 1][j - 1] == true) { counter = counter + 1; } if (initialMatrix[i + 1][j] == true) { counter = counter + 1; } else {   }   // if the counter is in the birth range, set that spot // as true if (counter >= birthLow && counter <= birthHigh) { matrixUpdate[i][j] = true; }   }   // if initMatrix was true, look to see if life will die else {   int counter2 = 0;   // these if statements test each spot neighboring spot // for // life // if life is found, counter will increase by 1 if (initialMatrix[i - 1][j - 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i - 1][j] == true) { counter2 = counter2 + 1; } if (initialMatrix[i - 1][j + 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i][j - 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i][j + 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i + 1][j + 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i + 1][j - 1] == true) { counter2 = counter2 + 1; } if (initialMatrix[i + 1][j] == true) { counter2 = counter2 + 1; } // if counter is outside of the death range, life is // eliminated if (counter2 >= liveHigh || counter2 <= liveLow) { matrixUpdate[i][j] = false; } else {   } } } } } } }

And what is your question?

Originally Posted by nWeid1

But, my teacher gave us a sample output and mine does not match hers. There is an error somewhere in my alterMatrix method, but I can't find where. Can you guys find it? Thanks a lot.

Find a 9-cell neighbourhood in your GoL whose centre cell changes to a different next state from the same cell in the same neighbourhood state in your teacher's output. Is your teacher's update correct and yours wrong? Show us the 9 cells before the update and the 9 cells (with the 'wrong' state in the centre) afterwards. I suspect you'll know yourself what is wrong when you do that.