prototype.c

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