life.cpp

数据结构与程序设计教材源码 数据结构与程序设计教材源码

 
void Life::print()
/*   
Pre:  The Life object contains a configuration.
Post: The configuration is written for the user.
 */

{
   int row, col;
   cout << "\nThe current Life configuration is:" <<endl;
   for (row = 1; row <= maxrow; row++) {
      for (col = 1; col <= maxcol; col++)
         if (grid[row][col] == 1) cout << '*';
         else cout << ' ';
      cout << endl;
   }
   cout << endl;
}
 
int Life::neighbor_count(int row, int col)
/*   
Pre:  The Life object contains a configuration, and the coordinates
row and col define a cell inside its hedge.
Post: The number of living neighbors of the specified cell is returned.
 */

{
   int i, j;
   int count = 0;
   for (i = row - 1; i <= row + 1; i++)
      for (j = col - 1; j <= col + 1; j++)
         count += grid[i][j];  //  Increase the count if neighbor is alive.
   count -= grid[row][col]; //  Reduce count, since cell is not its own neighbor.
   return count;
}
 
void Life::update()
/*   
Pre:  The Life object contains a configuration.
Post: The Life object contains the next generation of configuration.
 */

{
   int row, col;
   int new_grid[maxrow + 2][maxcol + 2];

   for (row = 1; row <= maxrow; row++)
      for (col = 1; col <= maxcol; col++)
         switch (neighbor_count(row, col)) {
         case 2:
            new_grid[row][col] = grid[row][col];  //  Status stays the same.
            break;
         case 3:
            new_grid[row][col] = 1;                //  Cell is now alive.
            break;
         default:
            new_grid[row][col] = 0;                //  Cell is now dead.
         }

   for (row = 1; row <= maxrow; row++)
      for (col = 1; col <= maxcol; col++)
         grid[row][col] = new_grid[row][col];
}
 
void Life::initialize()
/*   
Pre:  None.
Post: The Life object contains a configuration specified by the user.
 */

{
   int row, col;
   for (row = 0; row <= maxrow+1; row++)
      for (col = 0; col <= maxcol+1; col++)
         grid[row][col] = 0;
   cout << "List the coordinates for living cells." << endl;
   cout << "Terminate the list with the the special pair -1 -1" << endl;
   cin >> row >> col;

   while (row != -1 || col != -1) {
      if (row >= 1 && row <= maxrow)
         if (col >= 1 && col <= maxcol)
            grid[row][col] = 1;
         else
            cout << "Column " << col << " is out of range." << endl;
      else
         cout << "Row " << row << " is out of range." << endl;
      cin >> row >> col;
   }
}
 
void instructions()
/*   
Pre:  None.
Post: Instructions for using the Life program have been printed.
 */
{
   cout << "Welcome to Conway's game of Life." << endl;
   cout << "This game uses a grid of size "
        << maxrow << " by " << maxcol << " in which" << endl;
   cout << "each cell can either be occupied by an organism or not." << endl;
   cout << "The occupied cells change from generation to generation" << endl;
   cout << "according to the number of neighboring cells which are alive."
        << endl;
}