2 files changed, 178 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 378a202..6aeb578 100644
--- a/Makefile
+++ b/Makefile
@@ -5,11 +5,11 @@ PREFIX = /usr/local
 
 .PHONY: all install
 
-all: temperaturUmrechner matrixMult findMaxOfFloats
+all: temperaturUmrechner matrixMult findMaxOfFloats gameOfLife
 
 install:
         mkdir -p $(PREFIX)/bin
-        install -m 0755 -t $(PREFIX)/bin temperaturUmrechner matrixMult findMaxOfFloats
+        install -m 0755 -t $(PREFIX)/bin temperaturUmrechner matrixMult findMaxOfFloats gameOfLife
         mkdir -p $(PREFIX)/share
         install -m 0644 -t $(PREFIX)/share floats.txt
 
@@ -21,3 +21,6 @@ matrixMult:
 
 findMaxOfFloats:
         $(CC) $(INCLUDES) $(CCFLAGS) -o findMaxOfFloats findMaxOfFloats.c
+
+gameOfLife:
+        $(CC) $(INCLUDES) $(CCFLAGS) -o gameOfLife gameOfLife.c
diff --git a/gameOfLife.c b/gameOfLife.c
new file mode 100644
index 0000000..e016993
--- /dev/null
+++ b/gameOfLife.c
@@ -0,0 +1,173 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <unistd.h>
+#include <string.h>
+
+#define RANDOM_SEED time(NULL)
+
+typedef enum CellState { DEAD, ALIVE } CellState;
+
+void printUsage()
+{
+  printf("usage: gameOfLife [-x <SIZE>] [-y <SIZE>] [-d <FLOAT>] [-s <SECONDS>]\n"
+         "  -d <FLOAT> sets density of life cells at game start\n"
+         "  -s <SECONDS> time to sleep between rounds\n"
+         );
+}
+
+void initBoard(CellState* board, unsigned int x, unsigned int y, float density)
+{
+  float roll;
+  
+  srand(RANDOM_SEED);
+  for (int i = 0; i < x * y; i++)
+    {
+      roll = (float)rand()/(float)RAND_MAX;
+      if (roll <= density)
+        board[i] = ALIVE;
+      else
+        board[i] = DEAD;
+    }
+}
+
+int boardEq(CellState* a, CellState* b, unsigned int x, unsigned int y)
+{
+  for (int i = 0; i < x * y; i++)
+    {
+      if (a[i] != b[i])
+        return 0;
+    }
+
+  return 1;
+}
+
+void evolve(CellState* board, CellState* newBoard, unsigned int width, unsigned int height)
+{
+  int liveNeighbours;
+  CellState* focus;
+  CellState* newFocus;
+  
+  for (int y = 0; y < height; y++)
+    for (int x = 0; x < width; x++)
+      {
+        focus = &(board[y * width + x]);
+        newFocus = &(newBoard[y * width + x]);
+        liveNeighbours = 0;
+
+        for (int n = (y <= 0) ? 0 : -1; n <= ((y + 1) >= height ? 0 : 1); n++)
+          for (int m = (x <= 0) ? 0 : -1; m <= ((x + 1) >= width ? 0 : 1); m++)
+            {
+              // fprintf(stderr, "(%d, %d) + (%d, %d)\n", x, y, m, n); // DEBUG
+              if (board[(y + n) * width + (x + m)] == ALIVE && !(n == 0 && m == 0))
+                liveNeighbours++;
+            }
+
+        if (liveNeighbours == 3)
+          *newFocus = ALIVE;
+        else if (*focus == ALIVE && liveNeighbours == 2)
+          *newFocus = ALIVE;
+        else
+          *newFocus = DEAD;
+      }
+}
+
+void printBoard(CellState* board, unsigned int width, unsigned int height)
+{
+  void drawHoriz() {
+    printf("+");
+    for (int x = 0; x < width; x++)
+      printf("-");
+    printf("+\n");
+  }
+
+  drawHoriz();
+  
+  for (int y = 0; y < height; y++)
+    {
+      printf("|");
+      for (int x = 0; x < width; x++)
+        if (board[y * width + x] == ALIVE)
+          {
+            printf("X");
+          }
+        else
+          {
+            printf(" ");
+          }
+      printf("|");
+      printf("\n");
+    }
+
+  drawHoriz();
+}
+
+void main(int argc, char* argv[])
+{
+  unsigned int x = 16;
+  unsigned int y = 16;
+  float d = 0;
+  float s = 1;
+
+  CellState* board;
+  CellState* newBoard;
+
+  int c;
+  
+  while ((c = getopt(argc, argv, "x:y:d:s:h?")) != -1)
+    {
+      switch (c)
+        {
+        case 'x':
+          sscanf(optarg, "%d", &x);
+          break;
+        case 'y':
+          sscanf(optarg, "%d", &y);
+          break;
+        case 'd':
+          sscanf(optarg, "%f", &d);
+          break;
+        case 's':
+          sscanf(optarg, "%f", &s);
+          break;
+        case 'h':
+        case '?':
+          printUsage();
+          exit(EXIT_SUCCESS);
+        default:
+          printUsage();
+          exit(2);
+        }
+    }
+
+  if (d < 0 || d > 1)
+    {
+      fprintf(stderr, "Densitiy needs to be in [0;1]\n");
+      exit(2);
+    }
+
+  if (s <= 0)
+    {
+      fprintf(stderr, "Sleep interval needs to be greater 0\n");
+      exit(2);
+    }
+
+  board = malloc(sizeof(CellState) * x * y);
+  newBoard = malloc(sizeof(CellState) * x * y);
+
+  memset(board, DEAD, sizeof(CellState) * x * y);
+  initBoard(newBoard, x, y, d);
+
+  while (! boardEq(board, newBoard, x, y))
+    {
+      printBoard(newBoard, x, y);
+
+      usleep((int)(s * 1e6));
+
+      memcpy(board, newBoard, sizeof(CellState) * x * y);
+      evolve(board, newBoard, x, y);
+    }
+  
+  free(board);
+  exit(EXIT_SUCCESS);
+}