Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

C++: #include <iostream>
#include <vector>

using namespace std;

void dfs(vector<vector<int> >& map, int y, int x, int H, int W, int index)
{
  int dx[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
  int dy[8] = {-1, -1, -1, 0, 0, 1, 1, 1};

  map[y][x] = index;
  for (int i = 0; i < 8; i++)
  {
    if (y + dy[i] >= 0 && y + dy[i] < H && x + dx[i] >= 0 && x + dx[i] < W){
      if (map[y + dy[i]][x + dx[i]] == 1)
      {
        dfs(map, y + dy[i], x + dx[i], H, W, index);
      }
    }
  }
}

int main()
{
  int W,H;
  int index = 2;
  while(1){
    cin >> W >> H;
    if(W == 0 && H == 0){
      break;
    }
    vector<vector<int> > map(H, vector<int>(W, 0));
    for (int i = 0; i < H; i++)
    {
      for (int j = 0; j < W;j++){
        cin >> map[i].at(j);
      }
    }
    for (int i = 0; i < H;i++){
      for (int j = 0; j < W;j++){
        if(map[i][j] == 1){
          dfs(map, i, j, H, W, index);
          index++;
        }
      }
    }

    cout << index - 2 << endl;
    index = 2;
    map.clear();
  }
  return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <math.h>
#include <numeric>
#include <algorithm>
#include <stack>
using namespace std;
int grid[51][51];
int w, h, ans;
void dfs(int i, int j){ //iが縦jが横
    if(i<0||j<0||grid[i][j]==0) return ;
    grid[i][j]=0;
    
    for(int n=-1; n<=1; ++n){
        for(int m=-1; m<=1; ++m){
            dfs(i+n, j+m);
        }
    }
    return ;
}
int main() {
    while(cin >> w >> h, w||h){
        
        for(int i=0; i<h; ++i){
            for(int j=0; j<w; ++j){
                cin >> grid[i][j];
            }
        }
        ans = 0;
        for(int i=0; i<h; ++i){
            for(int j=0; j<w; ++j){
                if(grid[i][j]==1){
                    dfs(i, j);
                    ans++;
                }
            }
        }
        cout << ans << endl;
    }
        
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;

vector<vector<int>> mp;

int dx[] = {1,1,0,-1,-1,-1,0,1};
int dy[] = {0,1,1,1,0,-1,-1,-1};

void dfs(int x, int y, int hight, int width){
   mp[x][y] = 0;
  
  for(int k = 0; k < 8; k++){
    int a = x+dx[k]; int b = y+dy[k];
    if( a < 0 || a >= hight || b < 0 || b >= width){ continue;}
    if( mp[a][b] == 0){ continue;}
    else if(mp[a][b] == 1){
   dfs(a,b ,hight,width);}}
  return  ;
}
  
  
int main(){

 int w,h;
  while( cin >> w >> h){
    if( w == 0 && h == 0){ break;}
    
    mp = vector<vector<int>> (h,vector<int>(w));
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){ cin >> mp[i][j];}}
    
    //reserching the number of rikuchi by using dfs method
    int ans = 0;
    for(int i = 0; i < h; i++){
      for(int j = 0; j < w; j++){
        if(mp[i][j]==0){ continue;}
        dfs(i,j,h,w); 
        ans++;
      }
    }
    
    
    cout << ans << endl;
  }
  
  return 0;}

C++: #include <bits/stdc++.h>
using namespace std;

int state[100][100];
bool reached[100][100];
int w,h;

int dx[8]={1,0,-1,0,1,-1,1,-1};
int dy[8]={0,1,0,-1,1,1,-1,-1};

void dfs(int x, int y) {

	if(x==0 || h<x || y==0 || w<y || state[x][y] == 0)
		return;
	if(reached[x][y] == true)
		return;

	reached[x][y]=true;

	for(int i=0; i<8; i++) {
		dfs(x+dx[i],y+dy[i]);
	}
}

int main() {

	while(1){
		cin >> w >> h;
		if(w==0 && h==0) {
			return 0;
		}
		memset(state, 0, sizeof(state));
		memset(reached, false, sizeof(reached));
		for(int i=1; i<=h; i++) {
			for(int j=1; j<=w; j++) {
				cin >> state[i][j];
			}
		}
		int count=0;
		for(int i=1; i<=h; i++) {
			for(int j=1; j<=w; j++) {
				if(reached[i][j]==true || state[i][j] == 0)
					continue;
				else{
					dfs(i,j);
					count++;
				}
			}
		}
		cout << count << endl;
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
int W,H;
int t[50][50];
void visit(int h,int w){
  t[h][w]=0;
  for(int nh=h-1;nh<h+2;nh++){
    for(int nw=w-1;nw<w+2;nw++){
      if(t[nh][nw]==1&&0<=nh&&0<=nw&&nh<H&&nw<W)visit(nh,nw);
    }
  }
}

int main(void){
  int a,b,c,n;
  while(1){
    cin>>W>>H;
    c=0;
    if(W==0&&H==0)break;
    for(int i=0;i<H;i++){
      for(int j=0;j<W;j++){
	cin>>t[i][j];
      }
    }
    for(int i=0;i<H;i++){
      for(int j=0;j<W;j++){
	if(t[i][j]==1){
	  c++;
	  visit(i,j);
	}
      }
    }
    cout<<c<<endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;

using ll=long long;
#define int ll

#define FOR(i,a,b) for(int i=int(a);i<int(b);i++)
#define REP(i,b) FOR(i,0,b)

int read(){
	int i;
	scanf("%lld",&i);
	return i;
}

int land[100][100]={0};
int dy[]={-1,-1,-1,0,0,1,1,1};
int dx[]={-1,0,1,-1,1,-1,0,1};
int cnt=0;

void isLand(int i,int j){
    if(land[i][j]==1){
    	land[i][j] = 0;
		REP(k,8){
			int newy=i+dy[k];
			int newx=j+dx[k];
			isLand(newy,newx);
		}
    }
}

signed main(){
	int w,h;
	while( w=read(),h=read(),w||h){
		cnt=0;
		
		REP(i,100){
			REP(j,100){
				land[i][j]=0;
			}
		}
		FOR(i,1,h+1){
			FOR(j,1,w+1){
				land[i][j]=read();
			}
		}
		
		FOR(i,1,h+1){
			FOR(j,1,w+1){
				if(land[i][j]==1){
					cnt++;
					isLand(i,j);
				}
			}
		}
		
		cout << cnt << endl;
	}
	
}