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 <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++: #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(ll i = 0; i < (n); ++i)
#define FOR(i, m, n) for(ll i = m; i < (n); i++)
#define all(x) (x).begin(),(x).end()
using namespace std;
typedef long long ll;
using vi = vector<int>;
using vii = vector<vi>;
using pii = pair<int, int>; 
using vl = vector<ll>;
using vll = vector<vl>;
using pll = pair<ll, ll>;

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

int w, h;
vector<vector<bool>> seen;
vii field;

void dfs(int r, int c){
    seen[r][c] = true;
    rep(i, 8){
        int nr = r + dy[i];
        int nc = c + dx[i];

        if(nr < 0 || nc < 0 || nr >= h || nc >= w) continue;
        if(field[nr][nc] == 0) continue;
        if(seen[nr][nc]) continue;
        
        dfs(nr, nc);
    }
}

int main() {
    while(true){
        cin >> w >> h;
        if(w == 0 && h == 0) return 0;
        field.assign(h, vi(w));
        rep(i, h){
            rep(j, w){
                cin >> field[i][j];
            }
        }
        
        int cnt = 0;
        seen.assign(h, vector<bool>(w, false));
        rep(i, h){
            rep(j, w){
                if(seen[i][j]) continue;
                if(field[i][j] == 0) continue;
                dfs(i, j);
                cnt++;
            }
        }

        cout << cnt << endl;
    }
}

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

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

void dfs(int y,int x,vector<vector<int> >&m){
    m[y][x]=0;
    for(int i=0;i<8;i++){
        int nexty=y+dy[i];
        int nextx=x+dx[i];
        if(nexty<0||nexty>m.size()-1||nextx<0||nextx>m[0].size()-1)continue;
        if(m[nexty][nextx]==1)dfs(nexty,nextx,m);
    }
}


int main(void){
    int h,w;
    int ans;
    vector<vector<int> >m;
    while(true){
        cin>>w>>h;
        if(h==0)break;
        ans=0;
        m=vector<vector<int> >(h,vector<int>(w));
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                cin>>m[i][j];
            }
        }
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                if(m[i][j]==1){dfs(i,j,m);ans++;}
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}

C++: #include <iostream>

using namespace std;

#define PIAR pair<int, int>
int field[52][52];
int dx[] = { -1,  0, 1, 0, -1,  1, 1, -1};
int dy[] = {0 , -1, 0, 1, -1, -1, 1,  1};

void rec(int x, int y) {
	field[x][y] = 0;
	for (int i = 0; i < 8; i++) {
		int nextX = x + dx[i];
		int nextY = y + dy[i];
		if (field[nextX][nextY] == 1) rec(nextX, nextY);
	}
}

int main() {
	int w, h;
	while (cin >> w >> h, w != 0 && h != 0) {
		for (int i = 0; i < 52; i++) {
			for (int j = 0; j < 52; j++) {
				field[i][j] = 0;
			}
		}

		for (int i = 1; i <= h; i++) {
			for (int j = 1; j <= w; j++) {
				cin >> field[i][j];
			}
		}

		int island = 0;
		for (int i = 1; i <= h; i++) {
			for (int j = 1; j <= w; j++) {
				//??¶?????¢???
				if (field[i][j] == 1) {
					rec(i, j);
					island++;
				}
			}
		}
		cout << island << endl;
	}
}

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

void explore(const int i, const int j, const int w, const int h, const std::array<std::array<int, 50>, 50>& state, std::array<std::array<bool, 50>, 50>& visited)
{
    for (int a = -1; a < 2; a++) {
        for (int b = -1; b < 2; b++) {
            if (0 <= i + a && i + a < h && 0 <= j + b && j + b < w && (a != 0 || b != 0) && !visited.at(i + a).at(j + b) && state.at(i + a).at(j + b) == 1) {
                visited.at(i + a).at(j + b) = true;
                explore(i + a, j + b, w, h, state, visited);
            }
        }
    }
}

int main()
{
    while (true) {
        int w, h;
        std::cin >> w >> h;
        if (w == 0 && h == 0) {
            break;
        }
        int max_land_id = 0;
        std::array<std::array<int, 50>, 50> state;
        std::array<std::array<bool, 50>, 50> visited;
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                std::cin >> state.at(i).at(j);
                visited.at(i).at(j) = false;
            }
        }
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                if (state.at(i).at(j) == 1 && !visited.at(i).at(j)) {
                    visited.at(i).at(j) = true;
                    explore(i, j, w, h, state, visited);
                    ++max_land_id;
                }
            }
        }
        std::cout << max_land_id << std::endl;
    }
    return 0;
}