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;

int W, H;
int f[55][55];
const int dx[] = {-1, -1, -1, +0, +0, +1, +1, +1};
const int dy[] = {-1, +0, +1, -1, +1, -1, +0, +1};

void dfs(int x, int y)
{
    f[y][x] = 0;
    for (int i = 0; i < 8; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        if (0 <= nx && nx < W && 0 <= ny && ny < H &&
            f[ny][nx] == 1) {
            dfs(nx, ny);
        }
    }
}

int main()
{
    while (cin >> W >> H, W) {
        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) {
                cin >> f[i][j];
            }
        }

        int res = 0;
        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) {
                if (f[i][j] == 1) {
                    res++;
                    dfs(j, i);
                }
            }
        }
        cout << res << endl;
    }
    return 0;
}

C++: #include <iostream>

using namespace std;

int W, H;
int field[55][55];

void input(void){
	cin >> W;
	cin >> H;

	for(int i = 0;i < H;i++){
		for(int j = 0;j < W;j++){
			cin >> field[i][j];
		}
	}
}

void dfs(int x, int y){
	field[x][y] = 0;

	for(int dx = -1;dx <= 1;dx++){
		for(int dy = -1;dy <= 1;dy++){
			int nx = x + dx, ny = y + dy;
			if(0 <= nx && nx < W && 0 <= ny && ny < H && field[nx][ny] == 1) dfs(nx, ny);
		}
	}

	return ;
}

int main(){
	while(1){
		int res = 0;
		input();
		if(W == 0 && H == 0) break;

		for(int i = 0;i < H;i++){
			for(int j = 0;j < W;j++){
				if(field[i][j] == 1){
					dfs(i, j);
					res++;
				}
			}
		}

		cout << res << endl;
	}

	return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <numeric>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <utility>
#include <sstream>
#include <complex>
#include <fstream>
#include <bitset>
#include <time.h>
#include <tuple>
#include <iomanip>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef vector<ll> V;
typedef complex<double> Point;

#define PI acos(-1.0)
#define EPS 1e-10
const ll INF = 1e12;
const ll MOD = 1e9 + 7;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define rep(i,N) for(int i=0;i<(N);i++)
#define ALL(s) (s).begin(),(s).end()
#define EQ(a,b) (abs((a)-(b))<EPS)
#define EQV(a,b) ( EQ((a).real(), (b).real()) && EQ((a).imag(), (b).imag()) )
#define fi first
#define se second
#define N_SIZE (1LL << 20)
#define NIL -1

ll sq(ll num) { return num*num; }
ll mod_pow(ll x, ll n) {
	if (n == 0)return 1;
	if (n == 1)return x%MOD;
	ll res = sq(mod_pow(x, n / 2));
	res %= MOD;
	if (n % 2 == 1) {
		res *= x;
		res %= MOD;
	}
	return res;
}
ll mod_add(ll a, ll b) { return (a + b) % MOD; }
ll mod_sub(ll a, ll b) { return (a - b + MOD) % MOD; }
ll mod_mul(ll a, ll b) { return a*b % MOD; }

int w, h;
int c[100][100];

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

void solve(int y, int x) {
	c[y][x] = 0;
	rep(i, 8) {
		int ny = y + dy[i];
		int nx = x + dx[i];
		if (ny >= 0 && ny < h&&nx >= 0 && nx < w) {
			if (c[ny][nx] == 1)solve(ny, nx);
		}
	}
}

int main() {
	while (cin >> w >> h&&w + h) {
		ll ans = 0;
		rep(i, h) {
			rep(j, w) {
				cin >> c[i][j];
			}
		}
		rep(i, h) {
			rep(j, w) {
				if (c[i][j] == 1) {
					ans++;
					solve(i, j);
				}
			}
		}
		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<queue>
#include<cstdlib>

#define LOOP(n,cnt) for(int cnt=0;cnt<n;++cnt)

using namespace std;

template <typename TYPE>
void printArray(TYPE* array, int size){
  LOOP(size,i) cout << array[i] << "\t" << flush;
  cout << endl;
}

int StringToInt(string str){
  return atoi(str.c_str());
}

#define MAX_W 50
#define MAX_H 50
int w,h,c[MAX_W][MAX_H];
int count = 0;

void dfs(int sy, int sx){
  for(int i=-1;i<=1;i++){
    for(int j=-1;j<=1;j++){
      int y = sy+i;
      int x = sx+j;
      if(sy>=0 && sx>=0 && sy<h && sx<w){
	if(c[y][x] == 1){
	  c[y][x] = 0;
	  dfs(y,x);         
	}
      }
    }
  }
}

int main(){
  while(true){
    cin >> w;
    cin >> h;
    count = 0;
    if(w == 0 && h == 0) break;
    LOOP(h,y){
      LOOP(w,x){
	cin >> c[y][x];
      }    
    }
    
    LOOP(h,y){
      LOOP(w,x){
	if(c[y][x] == 1){
	  count++;
	  dfs(y,x);
	}
      }    
    }
    cout << count << endl;
  }
}