grid.cpp

ssd5-数据结构-optional-exercise3练习题答案保证正确

/*
*author:renhao
*Id:063449
*time:2008.11.13
*version:1.0
*/
#include <iostream>
#include <fstream>

using namespace std;

#include "grid.h"

// You do not need to alter function indexof.
int grid::indexof (int row, int col) const {
  return row*cols+col;
}

// You do not need to alter function infected.
bool grid::infected(int row, int col) const {
  return (area->operator[](indexof(row, col)) == INFECTED);
}

// You may need to alter the constructor
grid::grid (string file) {
  
  ifstream grid_file;

  grid_file.open (file.c_str());

  grid_file >> rows;
  grid_file >> cols;

  area = new vector<bool>(rows*cols, NOT_INFECTED);
  flag = new vector<bool>(rows*cols, NOT_INFECTED);
  while (true) { 
  
    int blob_row;
    int blob_col;

    grid_file >> blob_row;  
    grid_file >> blob_col;  

    if (grid_file.eof()) {
        break;
    }

    area->operator[](indexof(blob_row,blob_col)) = INFECTED;	
  }
  
  grid_file.close();
}

// You may need to alter the destructor
grid::~grid () {
  delete area;
}

// You will need to alter this function to display the
// plus signs (+) next to the cells that belong to
// a counted colony.
ostream &operator<<(ostream &stream, const grid& ob) {

  for (int row=0; row < ob.rows; row++) { 
    
    for (int col=0; col < ob.cols; col++) {
      stream << ob.area->operator[](ob.indexof(row, col));
	  //if its flag changed then count"+  "
	  if(ob.area->operator[](ob.indexof(row,col))== INFECTED&&ob.flag->operator [](ob.indexof(row,col))==INFECTED)
		  cout<<"+  ";
	  else
		 stream << "   ";
    }
    stream << endl;
  }

  stream << endl;
  return stream;
}

// Replace the return statement in this function with your
// recursive implementation of this method */
int grid::count (int row, int col) 
{
	static int infec_num = 0;//used to count the infected number.
    if(row>=0&&row<rows&&col>=0&&col<cols)//to ensure it is in the grid
	{
		//if it was infected and the flag is not changed
		if(infected(row,col)==INFECTED&&flag->operator [](indexof(row,col)) ==NOT_INFECTED)
		{
			infec_num++;
			flag->operator [](indexof(row,col)) = INFECTED;//to change the flag after it is been counted
			count(row,col-1);//the  8 ones maybe affected by it
			count(row,col+1);
			count(row-1,col);
			count(row+1,col);
			count(row-1,col-1);
			count(row-1,col+1);
			count(row+1,col-1);
			count(row+1,col+1);
		}
	}
	return infec_num;
}