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 <cstdio>
#include <queue>
#include <cstring>

using namespace std;

typedef pair<int, int> p;

int t_x[] = {1, 1, 1, 0, -1, -1, -1, 0};
int t_y[] = {1, 0, -1, -1, -1, 0, 1, 1};

int field[52][52];  

int main()
{
  while (true) {
    memset(field, 0, sizeof field);
    int width, height;
    scanf("%d %d", &width, &height);
    
    if (width == 0 && height == 0) break;
    
    for (int i = 1; i <= height; i++) {
      for (int j = 1; j <= width; j++) {
	scanf(" %d", &field[i][j]);
      }
    }
    
    queue<p> que;
    int c = 0;

    for (int i = 1; i <= height; i++) {
      for (int j = 1; j <= width; j++) {
	if (field[i][j] == 1) {
	  c++;
	  que.push(p(i, j));
	  field[i][j] = 0;
	  while (!que.empty()) {
	    p tmp = que.front();
	    que.pop();
	    //field[tmp.second][tmp.first] = 0;
	    //cout << tmp.first << ", " << tmp.second << endl;
	    for (int k = 0; k < 8; k++) {
	      int tx = tmp.second + t_x[k];
	      int ty = tmp.first + t_y[k];
	      //cout << ty << ", "<< tx << " =  "<< field[ty][tx] << endl;
	      if (field[ty][tx] == 1) {
		field[ty][tx] = 0;
		que.push(p(ty, tx));
	      }
	    }
	    //cout << endl;
	    //cout << i << " " << j << endl;
	    for (int k = 1; k <= height; k++) {
	      for (int l = 1; l <= width; l++) {
		//cout << field[k][l] << " ";
	      }
	      //cout << endl;
	    }
	    //cout << endl;
	  }
	}
      }     
    }
    cout << c << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#include <math.h>
using namespace std;
int W,H;
char field[60][60];
int dx[8]{-1,0,1,-1,1,-1,0,1};
int dy[8]{1,1,1,0,0,-1,-1,-1};

void dfs(int x,int y){
    field[x][y] = '0';
    for(int i = 0;i < 8;i++){
        int nx = x + dy[i];
        int ny = y + dx[i];
        if(0 <= nx && nx < H && 0 <= ny && ny < W && field[nx][ny] == '1'){
            dfs(nx,ny);
        }
    }
    return;
}
int main(){
    for(int k = 0;1;k++){
    cin >> W >> H;
    if(H == 0 && W == 0){
        return 0;
    }
    for(int i = 0;i < H;i++){
        for(int j = 0;j < W;j++){
            cin >> field[i][j];
        }
    }
    int ans = 0;
    bool frag = 0;
    for(int i = 0;i < H;i++){
        for(int j = 0;j < W;j++){
            if(field[i][j] == '1'){
                ans++;
                dfs(i,j);
            }
        }
    }
    cout << ans  << endl;
    }
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
// #define int long long

template <class T>
bool INRANGE(T x, T a, T b) { return a <= x && x <= b; }
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define RREP(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (int i = (a); i >= (b); --i)
#define ALL(v) (v).begin(), (v).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" \
                      << " " << __FILE__ << endl;

typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

int dh[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dw[] = {-1, 0, 1, -1, 1, -1, 0, 1};

vvi m;
int cnt;
vector<vector<bool>> visited;

void next(int h, int w) {
    if (m[h][w] == 0) return;
    if (visited[h][w]) return;
    visited[h][w] = true;

    REP(i, 8) {
        int nh = h + dh[i];
        int nw = w + dw[i];
        if (!INRANGE(nh, 0, (int)m.size()-1)) continue;
        if (!INRANGE(nw, 0, (int)m[0].size()-1)) continue;
        next(nh, nw);
    }
}

void dfs(int h, int w) {
    if (m[h][w] == 0) return;
    if (visited[h][w]) return;
    visited[h][w] = true;

    cnt++;
    REP(i, 8) {
        int nh = h + dh[i];
        int nw = w + dw[i];
        if (!INRANGE(nh, 0, (int)m.size()-1)) continue;
        if (!INRANGE(nw, 0, (int)m[0].size()-1)) continue;
        next(nh, nw);
    }
}

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

    while (true)
    {
        int w, h;
        cin >> w >> h;
        if (w == 0 and h == 0) break;

        m = vvi();
        REP(_, h) {
            vi l(w);
            //cin >> l;
            REP(i, w) cin >> l[i];
            m.emplace_back(l);
        }

        visited = vector<vector<bool>>(h, vector<bool>(w, false));
        cnt = 0;
        REP(hi, h) {
            REP(wi, w) {
                dfs(hi, wi);
            }
        }

        cout << cnt << endl;
    }
    
    


    return 0;
}

C++: #include <stdio.h>
#include <stack>

#define MAX_W 50
#define MAX_H 50
#define LAND 1
#define SEA 0
int map[MAX_H][MAX_W];
int h, w;
using namespace std;
stack<int> x, y;

bool input() {
  int i, j;

  scanf("%d %d", &w, &h);
  if (w == 0 && h == 0) return false;
  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      scanf("%d", &map[i][j]);
    }
  }

  return true;
}

int main() {
  int i, j, cnt;

  while (input()) {
    cnt = 0;
    for (i = 0; i < h; i++) {
      for (j = 0; j < w; j++) {
        if (map[i][j] == LAND) {
          cnt++;
          x.push(j);
          y.push(i);
          while (!x.empty() && !y.empty()) {
            int a = x.top();
            x.pop();
            int b = y.top();
            y.pop();
            if (a < 0 || w <= a || b < 0 || h <= b || map[b][a] == SEA)
              continue;
            map[b][a] = SEA;
            x.push(a - 1);
            y.push(b - 1);
            x.push(a - 1);
            y.push(b);
            x.push(a - 1);
            y.push(b + 1);
            x.push(a);
            y.push(b - 1);
            x.push(a);
            y.push(b + 1);
            x.push(a + 1);
            y.push(b - 1);
            x.push(a + 1);
            y.push(b);
            x.push(a + 1);
            y.push(b + 1);
          }
        }
      }
    }
    printf("%d\n", cnt);
  }

  return 0;
}