prototype.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <time.h>
   5 #include <unistd.h>
   6
   7 #define COLS 80
   8 #define ROWS 25
   9
  10 #define DEAD ' '
  11 #define ALIVE '#'
  12
  13 #define INIT_RATIO 4
  14
  15 #define STR(x) _STR (x)
  16 #define _STR(x) #x
  17
  18 static void
  19 clearscr ()
  20 {
  21   printf ("\e[1;1H\e[2J");
  22 }
  23
  24 static void
  25 print_row (char row[COLS])
  26 {
  27   printf ("%." STR (COLS) "s\n", row);
  28 }
  29
  30 static void
  31 print_grid (char grid[COLS * ROWS])
  32 {
  33   for (int i = 0; i < ROWS; i++)
  34     print_row (grid + i * COLS);
  35 }
  36
  37 static void
  38 init_grid (char grid[COLS * ROWS])
  39 {
  40   for (int i = 0; i < COLS * ROWS; i++)
  41     {
  42       if (rand () % INIT_RATIO)
  43         grid[i] = DEAD;
  44       else
  45         grid[i] = ALIVE;
  46     }
  47 }
  48
  49 static char
  50 get_state (char grid[COLS * ROWS], int row, int col)
  51 {
  52   if (row < 0 || row >= ROWS || col < 0 || col >= COLS)
  53     return DEAD;
  54
  55   return grid[row * COLS + col];
  56 }
  57
  58 static int
  59 alive_neighbours (char grid[COLS * ROWS], int idx)
  60 {
  61   int row = idx / COLS;
  62   int col = idx % COLS;
  63   int neighbours = 0;
  64
  65   for (int i = -1; i <= 1; i++)
  66     for (int j = -1; j <= 1; j++)
  67       if (get_state (grid, row + i, col + j) == ALIVE)
  68         neighbours++;
  69
  70   if (get_state (grid, row, col) == ALIVE)
  71     neighbours--;
  72
  73   return neighbours;
  74 }
  75
  76 static char
  77 next_state (char grid[COLS * ROWS], int idx)
  78 {
  79   int n = alive_neighbours (grid, idx);
  80
  81   if (get_state (grid, idx / COLS, idx % COLS) == ALIVE)
  82     {
  83       if (n < 2 || n > 3)
  84         return DEAD;
  85
  86       return ALIVE;
  87     }
  88
  89   if (n == 3)
  90     return ALIVE;
  91
  92   return DEAD;
  93 }
  94
  95 static void
  96 update_grid (char grid[COLS * ROWS])
  97 {
  98   char new[COLS * ROWS];
  99
 100   for (int i = 0; i < COLS * ROWS; i++)
 101     new[i] = next_state (grid, i);
 102
 103   memcpy (grid, new, COLS * ROWS);
 104 }
 105
 106 int
 107 main ()
 108 {
 109   char grid[COLS * ROWS];
 110
 111   srand (time (0));
 112   init_grid (grid);
 113
 114   do
 115     {
 116       clearscr ();
 117       print_grid (grid);
 118       update_grid (grid);
 119     }
 120   while (getchar () != 'q');
 121
 122   return 0;
 123 }