Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var route [][]int

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(h, w int) {
	if route[h][w] == 0 {
		return
	}

	route[h][w] = 0
	for _, x := range []int{-1, 0, 1} {
		for _, y := range []int{-1, 0, 1} {
			if route[h+x][w+y] == 0 {
				continue
			}
			dfs(h+x, w+y)
		}
	}
}

func main() {
	writer := bufio.NewWriter(os.Stdout)
	for {
		w, h := scanInt(), scanInt()
		if w == 0 && h == 0 {
			break
		}

		route = make([][]int, h+2)
		route[0] = make([]int, w+2)
		for i := 1; i <= h; i++ {
			route[i] = make([]int, w+2)
			for j := 1; j <= w; j++ {
				route[i][j] = scanInt()
			}
		}
		route[h+1] = make([]int, w+2)

		total := 0
		for i := 1; i <= h; i++ {
			for j := 1; j <= w; j++ {
				if route[i][j] == 1 {
					total++
					dfs(i, j)
				}
			}
		}
		fmt.Fprintln(writer, total)
	}
	writer.Flush()
}

C++: #include <iostream>
#include <map>
// #include <cstdio>
#include <stacK>

using namespace std;

int main() {
	while(1) {
	int w, h, data[52][52]={{0}};
	cin >> w >> h;
	if (w == 0 && h ==0) break;
	// memset(data, 0, sizeof(data));
	for (int i=1; i<=h; i++) {
		for (int j=1; j<=w; j++) {
			cin >> data[i][j];
		}
	}
	// for (int i=0; i<h; i++) {
	// 	for (int j=0; j<w; j++) {
	// 		cout << data[i][j] << "," ;
	// 	}cout <<endl;
	// }
	stack<pair<int, int> > s;
	int count=0;
	int H[8] = {-1, -1, -1, 0, 0, 1, 1, 1}, W[8] ={-1, 0, 1, -1, 1, -1, 0, 1};
	for(int i=1; i<=h; i++) {
		for (int j=1; j<=w; j++) {
			if (data[i][j]) {
				count++;
				s.push(make_pair(i, j));
				while (!(s.empty())) {
					pair<int, int> now;
					now = s.top();
					s.pop();
					data[now.first][now.second]=0;
					for (int k=0; k<8; k++) {
						if (data[H[k]+now.first][W[k]+now.second])
							s.push(make_pair(H[k]+now.first, W[k]+now.second));
					}
				}
			}
		}
	}
	cout << count <<endl;
}
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<string>
#include<queue>
#include<stack>
using namespace std;
#define INF (1 << 30) - 1
#define LINF 1LL << 60
const int MOD = 1000000007;
using ll = long long;
using P = pair<int, int>;

vector<int> dx{1, 0, -1, 0, 1, -1, 1, -1};
vector<int> dy{0, 1, 0, -1, -1, 1, 1, -1};

vector<vector<int>> g;
int w, h;

vector<vector<bool>> seen;
void dfs(int x, int y){
  seen[y][x] = true;
  for(int i = 0; i < 8; ++i){
    int nx = x + dx[i];
    int ny = y + dy[i];
    if(nx < 0 || w <= nx || ny < 0 || h <= ny)continue;
    else if(!g[ny][nx])continue;
    else if(seen[ny][nx])continue;
    dfs(nx, ny);
  }
}

int main(){
  while(true){
    cin >> w >> h;
    if(w == 0 && h == 0)return 0;
    g = vector<vector<int>>(h, vector<int>(w));
    for(int i = 0; i < h; ++i){
      for(int j = 0; j < w; ++j){
        cin >> g[i][j];
      }
    }

    seen = vector<vector<bool>>(h, vector<bool>(w, false));
    int cnt = 0;
    for(int i = 0; i < h; ++i){
      for(int j = 0; j < w; ++j){
        if(seen[i][j])continue;
        if(!g[i][j])continue;
        dfs(j, i);
        ++cnt;
      }
    }

    cout << cnt << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define REP(i,b) FOR(i,0,b)
#define INF 1e9

int w,h,c[50][50],i_num;
int dx[] = {1,0,-1}, dy[] = {1,0,-1};

void search(int x, int y){
  if(c[y][x] == 1 && x >=0 && x < w && y >=0 && y < h){
    c[y][x] = i_num;
    REP(i,3) REP(j,3){
      if(i != 0 || j != 0 || x-1 >= 0 || x+1 < w || y-1 >= 0 || y+1 < h)
      search(x+dx[i],y+dy[j]);
    }
  }
}

void solve(int X, int Y){
  i_num = 2;
  REP(i,20) REP(j,20) c[i][j] = 0;
  //0:ocean, 1:land, 2~:island_number

  REP(i,Y){
    REP(j,X){
      cin>>c[i][j];
    }
  }

  REP(i,Y){
    REP(j,X){
      if(c[i][j] == 1){
        search(j,i);
        i_num++;
      }
    }
  }

  cout<<i_num-2<<endl;
  /*REP(i,20){
     REP(j,20) cout<<c[i][j];
     cout<<endl;
  }*/
}

int main(){

  while(1) {
    cin>>w>>h;
    if(w == 0 && h == 0) break;
    solve(w,h);
  }

  return 0;
}

C++: #include <iostream>
#include <fstream>
#include <cstdlib>
#include <math.h>
#include <utility>
#include <algorithm>
#include <functional>
#include <vector>
#include <numeric>
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;
using vb = vector<bool>;
using Graph = vector<vector<int>>;

#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define REP(i,n) for(int i=0;i<n;i++)

vb seen;

void dfs(const Graph &G, int v) {
    seen[v] = true;
    for(auto next_v : G[v]) {
        if (seen[next_v]) continue;
        dfs(G, next_v);
    }
}

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

    int w, h;
    while(cin >> w >> h, w*h) {
        int map[h+1][w+1];
        REP(j, w+1) {
            map[0][j] = 0;
        }
        REP(i, h) {
            map[i+1][0] = 0;
            REP(j, w) {
                cin >> map[i+1][j+1];
            }
        }
        
        Graph G(w*h);
        FOR(i, 1, h+1) {
            FOR(j, 1, w+1) {
                if (map[i][j] == 1) {
                    int p1 = (i-1)*w+(j-1);
                    int p2;
                    if (map[i][j-1] == 1) {
                        p2 = (i-1)*w+(j-2);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j-1] == 1) {
                        p2 = (i-2)*w+(j-2);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j] == 1) {
                        p2 = (i-2)*w+(j-1);
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                    if (map[i-1][j+1] == 1) {
                        p2 = (i-2)*w+j;
                        G[p1].push_back(p2);
                        G[p2].push_back(p1);
                    }
                }
            }
        }

        seen.assign(w*h, false);
        int cnt = 0;
        REP(i, w*h) {
            if (seen[i]) continue;
            if (map[i/w+1][i%w+1] == 0) {
                seen[i] = true;
                continue;
            }
            cnt++;
            dfs(G, i);
        }
        cout << cnt << "\n";
    }
}

C++: #include<iostream>
#include<queue>

typedef std::pair<int, int> P;
int vx[] = { 0, 1, 0, -1, 1, 1, -1, -1 }, vy[] = { 1, 0, -1, 0, 1, -1, 1, -1 };
int w, h;
int map[51][51];

void bfs(int x, int y){

	map[y][x] = 0;

	std::queue<P>que;
	que.push(P(x, y));

	while (!que.empty()){

		P p = que.front();
		que.pop();

		for (int i = 0; i < 8; i++){
			int nx = p.first + vx[i], ny = p.second + vy[i];

			if (0 <= nx&&nx < w && 0 <= ny&&ny < h&&map[ny][nx] != 0){
				map[ny][nx] = 0;
				que.push(P(nx, ny));
			}
		}
	}

	return;
}

int main(){

	while (std::cin >> w >> h, w || h){

		int cnt = 0;

		memset(map, 0, sizeof(map));

		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				std::cin >> map[i][j];
			}
		}

		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				if (map[i][j] != 0){
					bfs(j, i);
					cnt++;
				}
			}
		}

		std::cout << cnt << std::endl;
	}

	return 0;
}