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 <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;

int h,w;
vector < vector <int> >c;

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

void dfs(int i, int j){
    c[i][j]=0;
    rep(dir,8){
        int vy=i+dy[dir];
        int vx=j+dx[dir];
        if(vy>=0&&vy<h&&vx>=0&&vx<w&&c[vy][vx]==1){
            dfs(vy,vx);
        }
    }
    return;
}

int main(){
    while(1){
        cin >> w >> h;
        if(h==0&&w==0)break;
        c = vector <vector <int> >(h, vector <int> (w) );
        rep(i,h)rep(j,w)cin >> c[i][j];
        int cnt=0;
        rep(i,h)rep(j,w){
            if(c[i][j]==1){
                dfs(i,j);
                cnt++;
            }
        }
        cout << cnt << endl;
    }
    return 0;
}

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

using ll = long long;
#define REP(i, n) for(int (i)=0; (i)< (n); ++i)
#define REPR(i, n) for(int (i)=(n); (i)>=0; --i)
#define FOR(i, n, m) for(int (i)=(n); (i)<(m); ++i)

int w, h;
vector<vector<int>> c(50, vector<int>(50)), homon(50, vector<int>(50));
int dx[] = {0, 1, 0, -1, 1, -1, -1, 1};
int dy[] = {1, 0, -1, 0, 1, -1, 1, -1};

void dfs(int y, int x){
  homon[y][x] = 1;
  REP(i, 8){
    int nx = x + dx[i], ny = y+dy[i];
    if(nx < 0 || w <= nx || ny < 0 || h <= ny) continue;
    if(homon[ny][nx] || c[ny][nx] == 0) continue;
    dfs(ny, nx);
  }
}

int main(){
  vector<int> ans;
  while(true){
    cin >> w >> h;
    if(w==0 && h== 0) break;
    REP(i, h){
      REP(j, w){
        cin >> c[i][j];
      }
    }
    REP(i, h){
      REP(j, w){
        homon[i][j] = 0;
      }
    }
    int cnt = 0;
    REP(i, h){
      REP(j, w){
        if(homon[i][j]==1 || c[i][j]==0) continue;
        dfs(i, j);
        cnt++;
      }
    }
    ans.push_back(cnt);
  }
  REP(i, ans.size()){
    cout << ans[i] << endl;
  }
  return 0;
}

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 newx=i+dy[k];
			int newy=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;
	}
	
}

C++: #include <iostream>
#include <vector>
using namespace std;
using Mat = vector<vector<bool>>;
int w, h;
const int dxy[10] = {0,1,1,1,0,-1,-1,-1,0,1};
void search(const Mat &map, Mat &searched, int x, int y, int dir) {
    if (x < 0 || w <= x || y < 0 || h <= y) {
        return;
    } else if (!map[x][y] || searched[x][y]) {
        return;
    }
    
    searched[x][y] = true;
    
    for (int i = 0; i < 8; ++i) {
        search(map, searched, x + dxy[i], y + dxy[i+2], i);
    }
}
int main(void){
    while (cin >> w >> h && w && h) {
        Mat map(w, vector<bool>(h, false));
        for (int y = 0; y < h; ++y) {
            for (int x = 0; x < w; ++x) {
                int c;
                cin >> c;
                map[x][y] = c;
            }
        }
        Mat searched(w, vector<bool>(h, false));
        int count = 0;
        for (int y = 0; y < h; ++y) {
            for (int x = 0; x < w; ++x) {
                if (searched[x][y] || !map[x][y]) continue;
                search(map, searched, x, y, -1);
                ++count;
            }
        }
        cout << count << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <queue>
using namespace std;
struct Point{int x,y;};
int main(){
  int w,h,p[51][51]={},v[51][51]={},i,j,k,o;
  queue <Point> q;
  Point n,b;
  cin >> w >> h;
  while(w!=0){
    for(j=0;j<h;j++){
      for(i=0;i<w;i++){
	cin >> p[i][j];
	v[i][j]=0;
      }
      
    }
    o=0;
    for(j=0;j<h;j++){
      for(i=0;i<w;i++){
	if(v[i][j]==0&&p[i][j]==1){
	  o++;
	  n.x=i;n.y=j;
	  q.push(n);
	  while(!q.empty()){
	    n=q.front();
	    q.pop();
	    v[n.x][n.y]=1;
	    if(n.x+1<w&&v[n.x+1][n.y]==0&&p[n.x+1][n.y]==1) {
	      b.x=n.x+1;b.y=n.y;
	      q.push(b);
	    }
	    if(n.y+1<h&&v[n.x][n.y+1]==0&&p[n.x][n.y+1]==1) {
	      b.x=n.x;b.y=n.y+1;
	      q.push(b);
	    }
	    if(n.x-1>=0&&v[n.x-1][n.y]==0&&p[n.x-1][n.y]==1) {
	      b.x=n.x-1;b.y=n.y;
	      q.push(b);
	    }
	    if(n.y-1>=0&&v[n.x][n.y-1]==0&&p[n.x][n.y-1]==1) {
	      b.x=n.x;b.y=n.y-1;
	      q.push(b);
	    }
	    if(n.x+1<w&&n.y+1<h&&v[n.x+1][n.y+1]==0&&p[n.x+1][n.y+1]==1) {
	      b.x=n.x+1;b.y=n.y+1;
	      q.push(b);
	    }
	    if(n.x-1>=0&&n.y-1>=0&&v[n.x-1][n.y-1]==0&&p[n.x-1][n.y-1]==1) {
	      b.x=n.x-1;b.y=n.y-1;
	      q.push(b);
	    }
	    if(n.x+1<w&&n.y-1>=0&&v[n.x+1][n.y-1]==0&&p[n.x+1][n.y-1]==1) {
	      b.x=n.x+1;b.y=n.y-1;
	      q.push(b);
	    }
	    if(n.x-1>=0&&n.y+1<h&&v[n.x-1][n.y+1]==0&&p[n.x-1][n.y+1]==1) {
	      b.x=n.x-1;b.y=n.y+1;
	      q.push(b);
	    }
	  }
	}
      }
    }
    cout << o << endl;
    cin >> w >> h;
  }
  return 0;
}