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>
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,w+1){
			FOR(j,1,h+1){
				land[i][j]=read();
			}
		}
		
		FOR(i,1,w+1){
			FOR(j,1,h+1){
				if(land[i][j]==1){
					cnt++;
					isLand(i,j);
				}
			}
		}
		
		cout << cnt << endl;
	}
	
}

C++: #include <iostream>
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
int H,W;
bool fld[50][50];
int main(){
	queue<pair<int,int> > p;
	while(cin>>W>>H,W,H){
		for(int i=0;i<H;i++){
			for(int j=0;j<W;j++){
				cin>>fld[j][i];
			}
		}
		int cnt=0;
		for(int i=0;i<H;i++){
			for(int j=0;j<W;j++){
				if(fld[j][i]){
					cnt++;
					fld[j][i]=0;
					p.push(make_pair(j,i));
					while(!p.empty()){
						int x=p.front().first,y=p.front().second;
						fld[x][y]=0;
						p.pop();
						for(int dx=-1;dx<=1;dx++)for(int dy=-1;dy<=1;dy++){
							int nx=x+dx,ny=y+dy;
							if(nx>=0 && nx<W && ny>=0 && ny<H && fld[nx][ny]){
								p.push(make_pair(nx,ny));
							}
						}
					}
				}
			}
		}
		cout<<cnt<<endl;
	}
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<map>
#include<set>
#include<queue>
#include<cstdio>
#include<climits>
#include<cmath>
#include<cstring>
#include<string>
#include<sstream>

#define f first
#define s second
#define mp make_pair

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,c) for(__typeof((c).begin()) i=(c).begin(); i!=(c).end(); i++)
#define ALL(c) (c).begin(), (c).end()

#define MAX 1000
#define EPS (1e-10)
using namespace std;

typedef unsigned int uint;
typedef long long ll;

int w,h;
int  b[64][64];

void clustering(int x, int y, char num){
  if(b[y][x] == 0) return;

  b[y][x] = 0;

  REP(i,3) REP(j,3){
    int xx = x + j - 1;
    int yy = y + i - 1;
    if(xx >= 0 && xx <= w-1 && yy >= 0 && yy <= h-1)
      clustering(xx, yy, num);
  }
}

int main(){
  while(scanf("%d%d",&w,&h), w+h){
    int cl = 0;
    REP(i,h) REP(j,w) scanf("%d", &b[i][j]);
    REP(i,h) REP(j,w){
      if(b[i][j] == 1){
        clustering(j,i,b[i][j]);
        cl++;
      }
    }
    printf("%d\n",cl);
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<map>
#include<math.h>
#include<iomanip>
#include<set>
#include<numeric>
#include<cstring>
#include<cstdio>
#include<functional>
#include<bitset>
#include<limits.h>
#include<cassert>
#include<iterator>
#include<complex>
#include<stack>
using namespace std;
typedef  long long int lint;
typedef pair<int, int> P;
typedef pair<lint, lint> LLP;
#define rep(i, n) for (int i = 0; i < n; i++)
#define repr(i, n) for (int i = n; i >= 0; i--)
#define sort(v) sort((v).begin(), (v).end())
#define reverse(v) reverse((v).begin(), (v).end())
/*
vector<char>al(26);
al = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
vector<char>AL(26);
AL = {'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
*/

int main() {
	int W, H;
	vector<int>dx(8);
	vector<int>dy(8);
	dx = { 1,1,0,-1,-1,-1,0,1 };
	dy = { 0,1,1,1, 0,-1,-1,-1};
	while (cin >> W >> H, W != 0) {
		vector<vector<char>>field(H, vector<char>(W));
		rep(i, H) {
			rep(j, W) {
				cin >> field[i][j];
			}
		}
		int cnt = 0;
		rep(sy, H) {
			rep(sx, W) {
				if (field[sy][sx] == '1') {
					cnt++;
					queue<P>que;
					que.push({ sx,sy });
					field[sy][sx] = '0';
					while (!que.empty()) {
						int x = que.front().first;
						int y = que.front().second;
						que.pop();
						rep(i, 8) {
							int xx = x + dx[i];
							int yy = y + dy[i];
							if (xx >= 0 && xx < W && yy >= 0 && yy < H && field[yy][xx] == '1') {
								que.push({ xx,yy });
								field[yy][xx] = '0';
							}
						}
					}
				}
			}
		}
		cout << cnt << endl;
	}
}