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 <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const int MOD = 1000000007;

template <typename T>
void print(const T &v);

vector<vector<int>> grid(55, vector<int>(55, -1));
vector<vector<bool>> seen(55, vector<bool>(55, false));

void dps(int x, int y)
{
    int xs[8] = {1, -1, 0, 0, -1, -1, 1, 1};
    int ys[8] = {0, 0, 1, -1, -1, 1, -1, 1};
    for (int i = 0; i < 8; i++)
    {
        int nx = x + xs[i];
        int ny = y + ys[i];
        if (nx < 0 || ny < 0)
        {
            continue;
        }
        if (seen[nx][ny] || grid[nx][ny] != 1)
        {
            continue;
        }
        seen[nx][ny] = true;
        dps(nx, ny);
    }
}

void init()
{
    for (int i = 0; i < 55; i++)
    {
        for (int j = 0; j < 55; j++)
        {
            grid[i][j] = -1;
            seen[i][j] = false;
        }
    }
}
int main()
{
    while (1)
    {
        int w, h;
        cin >> w >> h;
        if (w == 0 || h == 0)
        {
            return 0;
        }
        init();
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w; j++)
            {
                cin >> grid[i][j];
            }
        }
        int cnt = 0;
        for (int i = 0; i < h; i++)
        {
            for (int j = 0; j < w; j++)
            {
                if (seen[i][j] || grid[i][j] != 1)
                {
                    continue;
                }
                ++cnt;
                dps(i, j);
            }
        }
        cout << cnt << endl;
    }
}

// Use For Debug
template <typename T>
void print(T const &v)
{
    for (int i = 0; i < v.size(); i++)
    {
        if (i)
            cout << ' ';
        cout << v[i];
    }
    cout << endl;
}

C++: #include <cstdio>

using namespace std;

char mp[60][60] = {0};
int dx[9] = {0, 0, 1, -1, 1, -1, 1, -1};
int dy[9] = {1, -1, 0, 0, 1, -1,-1,  1};

void def(int y, int x){
	mp[y][x] = 0;
	for (int i = 0; i < 8; i++){
		int ty = y + dy[i];
		int tx = x + dx[i];
		if (mp[ty][tx] == '1') def(ty, tx);
	}
}

int main()
{
	int w, h;
	int pi, pj;
	int cnt;
	while (scanf("%d %d", &w, &h), !(w == 0 && h == 0)){
		cnt = 0;
		
		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				scanf("%s", &mp[i][j]);
			}
		}
		
		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				if (mp[i][j] == '1'){
					def(i, j);
					cnt++;
				}
			}
		}
		
		printf("%d\n", cnt);
	}
}