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;
typedef long long L;
L X[]={0,1,1,1,0,-1,-1,-1};
L Y[]={1,1,0,-1,-1,-1,0,1};
L h,w,mark[51][51],c=0;
L grid[51][51];
void call(L x,L y){
    mark[x][y]=1;
    for(L i=0;i<8;i++){
        L xx=X[i]+x,yy=Y[i]+y;
        if((xx>=0&&xx<h &&yy >=0&&yy<w) && grid[xx][yy] &&mark[xx][yy]==0){
            call(xx,yy);
        }
    }
}
int main()
{
    while(scanf("%lld%lld",&w,&h)&& w||h ){
        for(L i=0;i<h;i++){
            for(L j=0;j<w;j++)scanf("%lld",&grid[i][j]);
        }
        for(L i=0;i<h;i++){
            for(L j=0;j<w;j++){
                if(!mark[i][j] && grid[i][j]){
                    c++;
                    call(i,j);
                }
            }
        }
        printf("%lld\n",c);c=0;
        memset(mark,0,sizeof(mark));
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#define rep(i, n) for(int i = 0; i < n; i++)
using namespace std;
using Graph = vector<vector<int>>;

int H, W;
vector<int> f1{-1, -1, -1, 0, 0, 0, 1, 1, 1};
vector<int> f2{-1, 0, 1, -1, 0, 1, -1, 0, 1};
void dfs(Graph &G, int h, int w){
  G[h][w] = -1;
  rep(i, 9){
    int nh = h + f1[i];
    int nw = w + f2[i];
    if (nh < 0 || nw < 0 || nh >= H || nw >= W) continue;
    if (G[nh][nw] == -1 || G[nh][nw] == 0) continue;
    dfs(G, nh, nw);
  }
}

int main(){
  while(1){
    cin >> W >> H;
    if (H == 0 && W == 0) break;
    Graph G(H, vector<int>(W));
    rep(i, H)rep(j, W) cin >> G[i][j];
    int count = 0;
    rep(i, H)rep(j, W){
      if (G[i][j] == -1 || G[i][j] == 0) continue;
      dfs(G, i, j);
      count++;
    }
    cout << count << endl;
  }
  
  return 0;
}

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

using std::cin;
using std::cout;
using std::endl;

int main(void) {
	int w,h;
	cin >> w;
	cin >> h;

	while (w!=0||h!=0) {
		int count = 0;
		std::stack<int> st_x;
		std::stack<int> st_y;
		int xn,yn;
		int c;
		bool all = false;
		std::vector< std::vector<bool> > island(w+2, std::vector<bool>(h+2));
		for (int i = 0; i < h+2; i++) {
			for (int j = 0; j < w+2; j++) {
				if (i==0||i==h+1||j==0||j==w+1) {
					island[i][j] = false;
				} else {
					cin >> c;
					if (c==1) {
						island[i][j] = true;
						st_x.push(j);
						st_y.push(i);
					} else {
						island[i][j] = false;
					}
				}
			}
		}

		while (!st_x.empty()) {
			xn = st_x.top();
			yn = st_y.top();
			st_x.pop();
			st_y.pop();
			if (island[xn][yn]) {
				std::stack<int> st_xn,st_yn;
				island[xn][yn] = false;
				count++;
				st_xn.push(xn);
				st_yn.push(yn);
				while (!st_xn.empty()) {
					xn = st_xn.top();
					yn = st_yn.top();
					st_xn.pop();
					st_yn.pop();
					if (island[xn+1][yn]) {
						st_xn.push(xn+1);
						st_yn.push(yn);
						island[xn+1][yn] = false;
					}
					if (island[xn-1][yn]) {
						st_xn.push(xn-1);
						st_yn.push(yn);
						island[xn-1][yn] = false;
					}
					if (island[xn+1][yn+1]) {
						st_xn.push(xn+1);
						st_yn.push(yn+1);
						island[xn+1][yn+1] = false;
					}
					if (island[xn+1][yn-1]) {
						st_xn.push(xn+1);
						st_yn.push(yn-1);
						island[xn+1][yn-1] = false;
					}
					if (island[xn-1][yn+1]) {
						st_xn.push(xn-1);
						st_yn.push(yn+1);
						island[xn-1][yn+1] = false;
					}
					if (island[xn-1][yn-1]) {
						st_xn.push(xn-1);
						st_yn.push(yn-1);
						island[xn-1][yn-1] = false;
					}
					if (island[xn][yn+1]) {
						st_xn.push(xn);
						st_yn.push(yn+1);
						island[xn][yn+1] = false;
					}
					if (island[xn][yn-1]) {
						st_xn.push(xn);
						st_yn.push(yn-1);
						island[xn][yn-1] = false;
					}
				}
			}
		}
		cout << count << endl;

		cin >> w;
		cin >> h;
	}
		return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) FOR(i,0,n)
#define repr(i,n) for(int i=(n)-1;0<=i;--i)
#define each(e,v) for(auto&& e:(v))
#define all(v) begin(v),end(v)
#define dump(x) cerr<<#x<<": "<<(x)<<endl
#define INF 100000000
#define IINF 9999999999999;
using vint = vector<int>;
using ll = long long;
using vll = vector<ll>;
template <class T> void chmin(T& a, const T& b) { a = min(a, b); }
template <class T> void chmax(T& a, const T& b) { a = max(a, b); }

bool earth[51][51];

void erase_island(int h, int w) {
    earth[h][w] = false;
    //cout << "# " << h << " " << w << endl;
    if(earth[h - 1][w - 1]) erase_island(h - 1, w - 1);
    if(earth[h - 1][w]) erase_island(h - 1, w);
    if(earth[h - 1][w + 1]) erase_island(h - 1, w + 1);
    if(earth[h][w + 1]) erase_island(h, w + 1);
    if(earth[h + 1][w + 1]) erase_island(h + 1, w + 1);
    if(earth[h + 1][w]) erase_island(h + 1, w);
    if(earth[h + 1][w - 1]) erase_island(h + 1, w - 1);
    if(earth[h][w - 1]) erase_island(h, w - 1);
}

int main() {
    //ofstream outputfile("output.txt");
    int w, h;
    while(cin >> w >> h, w + h) {
        if(w == 0 && h == 0) break;
        int temp;
        rep(i, h) {
            rep(j, w) {
                cin >> temp;
                if(temp == 0) earth[i][j] = false;
                else earth[i][j] = true;
            }
        }

        int ans = 0;
        rep(i, h) {
            rep(j, w) {
                if(earth[i][j]) {
                    erase_island(i, j);
                    ++ans;
                }
            }
        }

        cout << ans << endl;
    }

    return 0;
}