Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include <iostream>
#include <vector>
using namespace std;

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

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

    // 八方向を探索
    for (int dh = -1; dh <= 1; ++dh) {
        for (int dw = -1; dw <= 1; ++dw) {
            int nh = h + dh, nw = w + dw;

            // 場外アウトしたり、0 だったりはスルー
            if (nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
            if (field[nh][nw] == 0) continue;

            // 再帰的に探索
            dfs(nh, nw);
        }
    }
}

int main() {
    // 入力受け取り
    while (cin >> W >> H) {
        if (H == 0 || W == 0) break;
        field.assign(H, vector<int>(W, 0));
        for (int h = 0; h < H; ++h) for (int w = 0; w < W; ++w) cin >> field[h][w];

        // 探索開始
        int count = 0;
        for (int h = 0; h < H; ++h) {
            for (int w = 0; w < W; ++w) {
                if (field[h][w] == 0) continue; // 残島じゃなかったらスルー
                dfs(h, w);
                ++count;
            }
        }
        cout << count << endl;
    }
}

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<functional>
#include<limits>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

#define MOD 1000000007
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL

#define MAX 50
#define NIL -1

static char M[MAX][MAX];
static int color[MAX][MAX];
int W, H;

void dfs(int h, int w, int c) {
	color[h][w] = c;
	if (h != H - 1 && M[h + 1][w] == '1'&&color[h + 1][w] == NIL)
		dfs(h + 1, w, c);
	if (h != 0 && M[h - 1][w] == '1'&&color[h - 1][w] == NIL)
		dfs(h - 1, w, c);
	if (w != W - 1 && M[h][w + 1] == '1'&&color[h][w + 1] == NIL)
		dfs(h, w + 1, c);
	if (w != 0 && M[h][w - 1] == '1'&&color[h][w - 1] == NIL)
		dfs(h, w - 1, c);

	if (h != H - 1 && w != W - 1 && M[h + 1][w + 1] == '1'&&color[h + 1][w] == NIL)
		dfs(h + 1, w + 1, c);
	if (h != 0 && w != 0 && M[h - 1][w - 1] == '1'&&color[h - 1][w - 1] == NIL)
		dfs(h - 1, w - 1, c);
	if (h != 0 && w != W - 1 && M[h - 1][w + 1] == '1'&&color[h - 1][w + 1] == NIL)
		dfs(h - 1, w + 1, c);
	if (h != H - 1 && w != 0 && M[h + 1][w - 1] == '1'&&color[h + 1][w - 1] == NIL)
		dfs(h + 1, w - 1, c);
}


int main() {
	while (cin >> W >> H&&H&&W) {
		for (int h = 0; h < H; h++) {
			for (int w = 0; w < W; w++) {
				cin >> M[h][w];
			}
		}
		fill(color[0], color[MAX], NIL);
		int c = 0;
		for (int h = 0; h < H; h++) {
			for (int w = 0; w < W; w++) {
				if (color[h][w] == NIL&&M[h][w] == '1') { dfs(h, w, c++); }
			}
		}
		cout << c << endl;
	}
	return 0;
}

C++: //
//  main.cpp
//  ICPC2009B
//
//  Created by aki33524 on 2014/07/02.
//  Copyright (c) 2014年 aki33524. All rights reserved.
//

#include <iostream>
using namespace std;

int H, W;
int field[50][50];
int dh[] = {0, 0, 1, -1};
int dw[] = {1, -1, 0, 0};

void dfs(int h, int w){
    field[h][w] = 0;
    for(int i=-1; i<=1; i++){
        for(int j=-1; j<=1; j++){
            int nh = h + i;
            int nw = w + j;
            if(0<=nh&&nh<H && 0<=nw&&nw<W && field[nh][nw])
                dfs(nh, nw);
        }
    }
}

void solve(){
    int ans = 0;
    for(int h=0; h<H; h++){
        for(int w=0; w<W; w++){
            if(field[h][w]){
                dfs(h, w);
                ans++;
            }
        }
    }
    cout << ans << endl;
}

int main(int argc, const char * argv[])
{
    while(cin >> W >> H, H|W){
        for(int h=0; h<H; h++){
            for(int w=0; w<W; w++){
                cin >> field[h][w];
            }
        }
        solve();
    }
    
    return 0;
}

C++: #include <bits/stdc++.h>
#include <vector>
#include <numeric>
#define PI 3.14159265358979323846
#define MAXINF (1e18L)
#define INF (1e9L)
#define EPS (1e-9)
#define MOD ((ll)(1e9+7))
#define REP(i, n) for(int i=0;i<int(n);++i)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define RREP(i, n) for(int i=int(n)-1;i>=0;--i)
#define ALL(v) v.begin(),v.end()
#define FIND(v,x) (binary_search(ALL(v),(x)))
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort(ALL(v));reverse(ALL(v))
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl
#define Yes(n) cout<<((n)?"Yes":"No")<<endl
#define YES(n) cout<<((n)?"YES":"NO")<<endl
#define pb push_back
#define fi first
#define se second
using namespace std;
template<class A>void pr(A a){cout << (a) << endl;}
template<class A,class B>void pr(A a,B b){cout << a << " "  ;pr(b);}
template<class A,class B,class C>void pr(A a,B b,C c){cout << a << " " ;pr(b,c);}
template<class A,class B,class C,class D>void pr(A a,B b,C c,D d){cout << a << " " ;pr(b,c,d);}
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll,ll> pll;

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

bool dfs(int x, int y){
    if(lake[x][y]==0) return false;

    int dx[8]={-1,1,0,0,1,1,-1,-1};
    int dy[8]={0,0,-1,1,1,-1,1,-1};
    
    lake[x][y] = 0;

    REP(i, 8){
        int nx = x + dx[i]; 
        int ny = y + dy[i];
        if(0 <= nx && nx < h && 0 <= ny && ny < w && lake[nx][ny] == 1){
            dfs(nx,ny);
        } 
    }
    return true;
}

int main(void)
{
    vector<int> ans;

    while(1){
        cin >> w >> h;
        if(w == 0 && h == 0) break;
        REP(i, h){
            REP(j, w){
                cin >> lake[i][j];
            }
        }

        int a = 0;
        REP(i, h){
            REP(j, w){
                a += dfs(i,j);
            }
        }
        ans.pb(a);
    }

    REP(i, ans.size()){
        pr(ans[i]);
    }
}

C++: #include <cstdio>
using namespace std;

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

void dfs(int x, int y)
{
	f[x][y]=0;
	for(int i=0; i<8; i++)
	{
		int tx=x+dx[i], ty=y+dy[i];
		if(tx<0||ty<0||tx>=W||ty>=H) continue;
		if(f[tx][ty]==0) continue;
		
		dfs(tx,ty);
	}
}

int main()
{
	while(scanf("%d%d", &W,&H), (W||H))
	{
		for(int i=0; i<H; i++)
		for(int j=0; j<W; j++)
			scanf("%d", &f[j][i]);
			
		int ans=0;
		for(int i=0; i<H; i++)
		for(int j=0; j<W; j++)
		{
			if(f[j][i])
			{
				ans++;
				dfs(j,i);
			}
		}
		
		printf("%d\n", ans);
	}
}