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;
const int mod = 1e9 + 7;
const int inf = (1 << 30) - 1;
const ll infll = (1LL << 61) - 1;
#define fast() ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define digit(N) cout << fixed << setprecision((N))

int H, W;
int dx[] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
int grid[50][50], visited[50][50];

int main()
{
    while (cin >> W >> H)
    {
        if (H == 0 && W == 0)
            return 0;

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

        int ans = 0, cnt = 0;
        queue<pair<int, int>> que;
        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                if (grid[i][j] == 1 && visited[i][j] == 0)
                {
                    que.push({i, j});

                    while (!que.empty())
                    {
                        auto p = que.front();
                        que.pop();
                        visited[p.first][p.second] = 1;
                        for (int k = 0; k < 8; k++)
                        {
                            int nx = p.first + dx[k], ny = p.second + dy[k];
                            if (nx < 0 || nx >= H)
                                continue;
                            if (ny < 0 || ny >= W)
                                continue;
                            if (visited[nx][ny])
                                continue;

                            visited[nx][ny] = 1;
                            if (grid[nx][ny] == 1)
                                que.push({nx, ny});
                        }
                    }
                    ans++;
                }
            }
        }

        cout << ans << endl;
    }
}

C++: #include <bits/stdc++.h>

using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;
using pint = pair<int, int>;
int dx[8] = {1, 0, -1, 0, 1, -1, 1, -1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const int MOD = 1000000009;
const long long INF = 1LL << 60;

void dfs(Graph& G, int y, int x) {
    int H = G.size();
    int W = G[0].size();
    G[y][x] = -1;
    for (int i = 0; i < 8; ++i) {
        int ny = y + dy[i];
        int nx = x + dx[i];
        if (ny < 0 || ny >= H || nx < 0 || nx >= W) continue;
        if (G[ny][nx] != 1) continue;
        dfs(G, ny, nx);
    }
}

int main() {
    while(1) {
        int W, H;
        cin >> W >> H;
        if (W == 0 && H == 0) break;
        Graph C(H, vector<int>(W, 0));
        for (int i = 0; i < H; ++i) {
            for (int j = 0; j < W; ++j) cin >> C[i][j];
        }
        int res = 0;
        for (int i = 0; i < H; ++i) {
            for (int j = 0; j < W; ++j) {
                if (C[i][j] == 1) {
                    ++res;
                    dfs(C, i, j);
                }
            }
        }
        cout << res << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <queue>
#include <climits>
#include <utility>

using namespace std;

int dfs( vector< vector<int> > &board, const int &h, const int &w, int y, int x )
{
	if ( !( 0 <= y && y < h && 0 <= x && x < w ) || 
		board[y][x] == 0 )
	{
		return 0;
	}

	board[y][x] = 0;

	for ( int i = -1; i <= 1; i++ )
	{
		for ( int j = -1; j <= 1; j++ )
		{
			dfs( board, h, w, y + i, x + j );
		}
	}
	return 1;
}

int main()
{
	while ( true )
	{
		int w, h;
		cin >> w >> h;

		if ( !( w | h ) )
		{
			break;
		}

		vector< vector<int> > board( h, vector<int>( w ) );

		for ( int i = 0; i < h; i++ )
		{
			for ( int j = 0; j < w; j++ )
			{
				cin >> board[i][j];
			}
		}

		int res = 0;

		for ( int i = 0; i < h; i++ )
		{
			for ( int j = 0; j < w; j++ )
			{
				res += dfs( board, h, w, i, j );
			}
		}

		cout << res << endl;
	}

	return 0;
}

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

int W,H;
vector<vector<int> > c;

void dfs(int h, int w){
    c[h][w] = 0;

    for(int i=-1;i<=1;++i){
        for(int j=-1;j<=1;++j){
            int nh = h + i, nw = w + j;

            if(nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
            if(c[nh][nw] == 0) continue;

            dfs(nh, nw);
        }
    }
}

int main(){
    while(cin >> W >> H){
        if(H == 0 || W == 0) break;
        c.assign(H, vector<int>(W, 0));
        for(int i=0;i<H;++i){
            for(int j=0;j<W;++j){
                cin >> c[i][j];
            }
        }

        int count = 0;
        for(int i=0;i<H;++i){
            for(int j=0;j<W;++j){
                if(c[i][j] == 0) continue;
                dfs(i, j);
                count ++;
            }
        }
        cout << count << endl;
    }
}

C++: #include <bits/stdc++.h>
#define debug(x) cerr << #x << ": " << x << '\n';
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = (int)1e9;

int w, h;
int c[51][51];
int dx[] = {1, -1, 0, 0, 1, 1, -1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, 1, -1};

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

int solve(){
	int res = 0;
	for(int i = 0; i < h; i++){
		for(int j = 0; j < w; j++){
			if(c[i][j] == 1){
				dfs(i, j);
				res++;
			}
		}
	}

	return res;
}

int main(void){
	while(scanf("%d%d", &w, &h) != EOF){
		if(w == 0 and h == 0) break;
		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				scanf("%d", &(c[i][j]));
			}
		}
		printf("%d\n", solve());
	}

	return 0;
}