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 in[100][100];
bool seen[100][100];
int ans =0;

void solve(int i,int j){
    //cout << i << " " << j << endl;
    if(i < 0 || j < 0 || i >= h || j >= w){
        return;
    }
    if(seen[i][j]){
        return;
    }
    if(in[i][j] == 0){
        return;
    }
    seen[i][j] = true;
    solve(i-1,j-1);
    solve(i-1,j);
    solve(i-1,j+1);
    solve(i,j-1);
    solve(i,j+1);
    solve(i+1,j-1);
    solve(i+1,j);
    solve(i+1,j+1);

}
int main(){
    while(1){
    cin >> w >> h;
    if(w == 0 && h == 0){
        break;
    }
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin >> in[i][j];
            seen[i][j] = false;
        }
    }
    ans = 0;
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(seen[i][j] == true || in[i][j] == 0){
            }
            else{
                solve(i,j);
                ans++;
            }
            
        }
    }
   
     cout << ans << endl;
    }
    return 0;
}

C++: #define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef pair<ll, ll> LP;

const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll LINF = 1e18;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const int ddx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const int ddy[8] = {0, 1, 1, 1, 0, -1, -1, -1};

int gcd(int a, int b) {
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

int lcm(int a, int b) { return a * b * gcd(a, b); }

bool compareP(pair<int, int> a, pair<int, int> b) {
    if (a.second != b.second) {
        return a.second < b.second;
    } else {
        return a.first < b.first;
    }
}

int w, h;
int mp[50][50];

void dfs(int h2, int w2) {
    mp[h2][w2] = 0;
    rep(i, 8) {
        int nw = w2 + ddx[i];
        int nh = h2 + ddy[i];
        if (nw >= 0 && nw < w && nh >= 0 && nh < h && mp[nh][nw] == 1)
            dfs(nh, nw);
    }
}

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

C++: /*
　　こんにちは。あたしはｶｳｶﾞｰﾙ。
　　redcoderになるためAtCoderを巡る旅をしてます。

　　　 　 ＿_
　　　 ヽ|＿_|ノ　　　　ﾓｫ
　　　　||‘‐‘||ﾚ　　_)_, ―‐ 、
　　　　/(Ｙ (ヽ＿ /・ ヽ　　 ￣ヽ
　　　　∠ ＿ ゝ　 ｀^ヽ ﾉ.::::_(ノヽ
　　　　 _/ヽ　 　　  /ヽ￣￣/ヽ
*/

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define dump(x) cout << #x << " = " << (x) << endl
#define YES(n) cout << ((n) ? "YES" : "NO") << endl
#define Yes(n) cout << ((n) ? "Yes" : "No") << endl
#define POSSIBLE(n) cout << ((n) ? "POSSIBLE" : "IMPOSSIBLE") << endl
#define Possible(n) cout << ((n) ? "Possible" : "Impossible") << endl

#define rep(i, n) REP(i, 0, n)                  // 0, 1, ..., n-1
#define REP(i, x, n) for(int i = x; i < n; i++) // x, x + 1, ..., n-1
#define FOREACH(x, a) for(auto &(x) : (a))

#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()

#define COUT(x) cout << (x) << endl

template <class T> inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T> inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}

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

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

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

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

            dfs(nh, nw);
        }
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    while(cin >> W >> H) {
        if(H == 0 || W == 0) break;
        field.assign(H, vector<int>(W, 0));
        rep(h, H) rep(w, W) cin >> field[h][w];

        int count = 0;
        rep(h, H) {
            rep(w, W) {
                if(field[h][w] == 0) continue;
                dfs(h, w);
                ++count;
            }
        }
        cout << count << endl;
    }
}

C++: #include <iostream>

using namespace std;

int w, h;
int c[55][55], ans;

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

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