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 <queue>
using namespace std;

int main(){
  bool map[52][52];
  int w,h;

  while(cin >> w >> h && w>0 && h>0){
    for(int i=0;i<52;i++){
      for(int j=0;j<52;j++)
        map[i][j]=false;
    }

    int land=0;

    for(int i=1;i<=h;i++){
      for(int j=1;j<=w;j++){
        int c;
        cin >> c;
        if(c==1) map[i][j]=true;
        land++;
      }
    }

    int visited=0,cnt=0;
    queue<int> cur;
    int d[8]={-w-3,-w-2,-w-1,-1,1,w+1,w+2,w+3};

    while(visited<land){
      cnt++;
      for(int i=0;i<(w+2)*(h+2);i++){
        if(map[i/(w+2)][i%(w+2)]){
          map[i/(w+2)][i%(w+2)]=false;
          visited++;
          cur.push(i);
          break;
        }
      }
      while(!cur.empty()){
        for(int i=0;i<8;i++){
          if(map[(cur.front()+d[i])/(w+2)][(cur.front()+d[i])%(w+2)]){
            map[(cur.front()+d[i])/(w+2)][(cur.front()+d[i])%(w+2)]=false;
            visited++;
            cur.push(cur.front()+d[i]);
          }
        }
        cur.pop();
      }
    }

    cout << cnt << endl;
  }

  return 0;
}

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

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

void solve(int x,int y){
	if(m[y][x] == 1){
		m[y][x] = 0;
		for(int i=-1;i<2;i++){
			for(int j=-1;j<2;j++){
				if(i==0&&j==0){
					continue;
				}
				if(y+i >= 0 && y+i < h && x+i >= 0 && x+i < w){
					solve(x+j,y+i);
				}
			}
		}
	}
}

int main(){
	while(true){
		int count=0;

		cin >> w >> h;
		if(w==0&&h==0){
			break;
		}

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

		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				if(m[i][j] == 1){
					solve(j,i);
					count++;
				}
			}
		}

		cout << count << endl;
	}
}

C++: #include<iostream>

using namespace std;

int idirs[] = {0, 0, 1, 1, 1, -1, -1, -1};
int jdirs[] = {1, -1, 0, 1, -1, 0, 1, -1};

int map[52][52];

void dfs(int i, int j) {
    if (!map[i][j]) return;
    map[i][j] = 0;
    for (int k = 0; k < 8; ++k) {
        dfs(i + idirs[k], j + jdirs[k]);
    }
}

int main() {
    while (1) {
        int w, h;

        cin >> w >> h;

        if (w == 0) break;

        for (int i = 0; i < 52; ++i)
            for (int j = 1; j < 52; ++j)
                map[i][j] = 0;

        for (int i = 1; i <= h; ++i) {
            for (int j = 1; j <= w; ++j) {
                cin >> map[i][j];
            }
        }

        int ans = 0;
        for (int i = 1; i <= h; ++i) {
            for (int j = 1; j <= w; ++j) {
                if (map[i][j] == 1) {
                    dfs(i, j);
                    ans++;
                }
            }
        }

        cout << ans << endl;
    }
}

C++: #include <iostream>
#include <stdio.h>
#include <algorithm>
#include <math.h>
#include <vector>
#include <string>
#include <sstream>
#include <numeric>
#include <set>
#include <map>
//#include <bits/stdc++.h>

#define rep(i, j) for(int i = 0; i < j; i++)
#define all(i) i.begin(), i.end()
#define ll long long
#define bl bool
#define nn printf("\n");
#define mod 1000000007

using namespace std;

int w, h, cnt = 0;

void srch(int x, int y, vector<vector<int>> &inp, vector < vector <bool>> &hit)
{
	if (x < 0 || w <= x || y < 0 || h <= y || inp[y][x] == 0) { return; }
	if (hit[y][x]) return;
	hit[y][x] = true;
	cnt += 1;
	srch(x + 1, y, inp, hit);
	srch(x - 1, y, inp, hit);
	srch(x, y + 1, inp, hit);
	srch(x, y - 1, inp, hit);
	srch(x + 1, y + 1, inp, hit);
	srch(x + 1, y - 1, inp, hit);
	srch(x - 1, y + 1, inp, hit);
	srch(x - 1, y - 1, inp, hit);
}
int main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	while (cin >> w >> h && w != 0 && h != 0)
	{
		vector<vector<int>> inp(h, vector<int>(w, 0));
		vector<vector<bool>> hit(h, vector<bool>(w, false));
		int ans = 0;
		rep(y, h) rep(x, w){ cin >> inp[y][x]; }
		rep(y, h) rep(x, w)
		{
			srch(y, x, inp, hit);
			if (cnt > 0) { ans += 1; }
			cnt = 0;
		}
		printf("%d\n", ans);
	}

	return 0;
}

C++: #include <iostream> // cout, endl, cin
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <cstdio> // printf
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set
#include <stack> // stack
#include <deque> // deque
#include <unordered_map> // unordered_map
#include <iomanip>
#include <unordered_set> // unordered_set
#include <bitset> // bitset
#include <cctype> // isupper, islower, isdigit, toupper, tolower
#include <math.h>
#include <cmath>
#include <stdlib.h>
#include <stdio.h>
using namespace std;
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; }
const int INF = 1001001000;
const int MOD = 1000000007;

long long gcd(long long a, long long b) {
    if (b == 0) return a;
    else return gcd(b, a % b);
}
long long lcm(long long a, long long b) {
    return a * b / gcd(a, b);
}

using Graph = vector<vector<int>>;
//再帰とかグラフを使うときは予めNの最大値のグローバル配列を取っておく
int N;
vector<int> E[200001];
bool shipment[15][15];
vector<bool> seen;
typedef pair<int, int> P;
int D[101];
//頂点状態を表すcolor[]において、0は未訪問、1は訪問中、2は完了を表す。
int color[101];
int find_time = 0;
char F[51][51];
int H, W;

void dfs(int x, int y) {
    F[x][y] = '0';
    for (int i = -1; i <= 1; i++) {
        for (int j = -1; j <= 1; j++) {
            int to_x = x + i; int to_y = y + j;
            if (to_x >= 0 && to_x < H && to_y >= 0 && to_y < W && F[to_x][to_y] == '1') dfs(to_x, to_y);
        }
    }
    return;
}

int main() {
    vector<int> ans;
    int output_count = 0;

    while (true) {
        cin >> H >> W; swap(H, W);
        if (H == 0 && W == 0) {
            break;
        }
        output_count++;
        for (int i = 0; i < H; i++) {
            for (int k = 0; k < W; k++) cin >> F[i][k];
        }
            int count = 0;
            for (int i = 0; i < H; i++) {
                for (int j = 0; j < W; j++) {
                    if (F[i][j] == '1') {
                        dfs(i, j);
                        count++;
                    }
                }
            }
            ans.push_back(count);
        
    }

    for (int i = 0; i < output_count; i++) cout << ans.at(i) << endl;
}