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<algorithm>
#include<map>
#include<queue>
using namespace std;
#define REP(i, a, n) for(int i=a; i<n; i++)
#define RREP(i, a, n) for(int i=n-1; i>=a; i--)
#define INF 1000000000
#define MP(a, b) make_pair(a, b)
#define F first
#define S second

int dy[8] = { -1, -1, 0, 1, 1, 1, 0, -1 };
int dx[8] = { 0, 1, 1, 1, 0, -1, -1, -1 };
int main() {
	int w, h;
	while (cin >> w >> h, w || h) {
		bool field[52][52];
		int num[52][52];
		REP(i, 0, h + 2) REP(j, 0, w + 2) {
			if (i == 0 || j == 0 || i == h + 1 || j == w + 1) field[i][j] = 0;
		}
		REP(i, 1, h + 1) REP(j, 1, w + 1) cin >> field[i][j];
		REP(i, 0, h + 2) REP(j, 0, w + 2) num[i][j] = 0;
		
		int cnt = 1;
		REP(i, 1, h + 1) {
			REP(j, 1, w + 1) {
				if (!field[i][j] || num[i][j] != 0) continue;

				num[i][j] = cnt;

				queue<pair<int, int>> q;
				q.push(MP(i, j));
				while (!q.empty()) {
					int y = q.front().F;
					int x = q.front().S;
					q.pop();

					REP(k, 0, 8) {
						int ny = y + dy[k];
						int nx = x + dx[k];
						if (field[ny][nx] && num[ny][nx] == 0) {
							num[ny][nx] = cnt;
							q.push(MP(ny, nx));
						}
					}
				}

				cnt++;
			}
		}

		int ans = 0;
		REP(i, 0, h + 2) REP(j, 0, w + 2) {
			ans = max(ans, num[i][j]);
		}
		cout << ans << endl;
	}
	return 0;
}

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

int w, h, c[51][51];
const int dx[8] = {-1,-1,-1, 0, 0,+1,+1,+1};
const int dy[8] = {-1, 0,+1,-1,+1,-1, 0,+1};


void dfs(int x, int y){
	c[y][x] = 0;
	for(int i = 0; i < 8; i++){
		int mx = x + dx[i], my = y + dy[i];
		if( mx < 0 || my < 0 || w <= mx || h <= my ) continue;
		
		if( c[my][mx] == 1 ) dfs(mx, my);
	}
}

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

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

int w,h;
int c[60][60];

void dfs(int x,int y){
    c[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<h&&0<=ny&&ny<w&&c[nx][ny]==1)dfs(nx,ny);
        }
    }
    
    return ;
}

int main(void){
    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>>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){
                    dfs(i,j);
                    res++;
                }
            }
        }
        cout<<res<<endl;
    }
    return 0;
}