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<utility>
#include<queue>
#include<map>
#define h first
#define w second
using namespace std;
typedef pair<int, int> P;

const int MAX_H = 55;
const int MAX_W = 55;

int grid[MAX_H][MAX_W];
bool is_checked[MAX_H][MAX_W];

void solve(int W, int H) {
    map<P, bool> is_exist;
    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) {
            cin >> grid[i][j];
            is_checked[i][j] = false;
            is_exist[P(i, j)] = true;
        }
    }
    queue<P> Q;
    int land_cnt = 0;
    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) {
            if (grid[i][j] == 1 && !is_checked[i][j]) {
                Q.push(P(i, j));
                is_checked[i][j] = true;
                while (!Q.empty()) {
                    P now_pos = Q.front();
                    Q.pop();
                    for (int k = -1; k <= 1; k++) {
                        for (int l = -1; l <= 1; l++) {
                            P new_pos = P(now_pos.h + k, now_pos.w + l);
                            if (!is_exist[new_pos]) continue;
                            if (is_checked[new_pos.h][new_pos.w]) continue;
                            if (grid[new_pos.h][new_pos.w] == 0) continue;
                            Q.push(new_pos);
                            is_checked[new_pos.h][new_pos.w] = true;
                        }
                    }
                }
                land_cnt++;
            }
        }
    }
    cout << land_cnt << endl;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int W, H;
    while (true) {
        cin >> W >> H;
        if (W == 0 && H == 0) break;
        solve(W, H);
    }
    return 0;
}

C++: # include <bits/stdc++.h>
# define rep(i, n) for(int i=0, i##_len=(n); i<i##_len; ++i)
# define Find(v,key) ((v).find(key) != (v).end())
# define cauto const auto
# define int long long
using namespace std;
template <class Type> inline constexpr bool InRange(const Type& x, const Type& fst, const Type& lst) { return (fst <= x) && (x < lst); }
void _cin(){} template <class Head, class... Tail> void _cin(Head&& head, Tail&&... tail){ cin >> head; _cin(forward<Tail>(tail)...); }
#define Cin(Type, ...) Type __VA_ARGS__; _cin(__VA_ARGS__)
#define Cinvv(Type, xs, h, w) vector<vector<Type>> xs(h, vector<int>(w)); rep(i, h) rep(j, w) cin >> xs[i][j]

# define mp(f,s) make_pair(f, s)

using P = pair<int, int>;
# define Y first
# define X second

struct phash {
    inline size_t operator ()(const pair<int,int>& p) const {
        const auto h1 = hash<int>()(p.first);
        const auto h2 = hash<int>()(p.second);
        return h1 ^ (h2 << 1);
    }
};

bool can(const vector<vector<int>>& c, int h, int w, P pos) {
    return InRange(pos.Y, (int)0, h)
       and InRange(pos.X, (int)0, w)
       and c[pos.Y][pos.X] == 1;
}

signed main() {
    while (true) {
        Cin(int, w, h);
        if (w == 0 and h == 0) break;
        Cinvv(int, c, h, w);

        set<P> visited;
        int ans = 0;
        rep (y, h) rep (x, w) {
            stack<P> stk;
            P ini = mp(y, x);
            if (!Find(visited, ini) and can(c, h, w, ini)) ans++;
            else continue;
            stk.push(ini);
            visited.insert(ini);

            while (!stk.empty()) {
                P now = stk.top(); stk.pop();
                for (int dy = -1; dy <= 1; ++dy) {
                    for (int dx = -1; dx <= 1; ++dx) {
                        P nxt = mp(now.Y + dy, now.X + dx);
                        if (!can(c, h, w, nxt)) continue;
                        if (Find(visited, nxt)) continue;
                        stk.push(nxt);
                        visited.insert(nxt);
                    }
                }
            }
        }

        cout << ans << "\n";
    }

    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<queue>
#include<cstdlib>

#define LOOP(n,cnt) for(int cnt=0;cnt<n;++cnt)

using namespace std;

template <typename TYPE>
void printArray(TYPE* array, int size){
  LOOP(size,i) cout << array[i] << "\t" << flush;
  cout << endl;
}

int StringToInt(string str){
  return atoi(str.c_str());
}

#define MAX_W 50
#define MAX_H 50
int w,h,c[MAX_W][MAX_H];
int count = 0;

void dfs(int sy, int sx){
  for(int i=-1;i<=1;i++){
    for(int j=-1;j<=1;j++){
      int y = sy+i;
      int x = sx+j;
      if(y>=0 && x>=0 && y<h && x<w){
	if(c[y][x] == 1){
	  c[y][x] = 0;
	  dfs(y,x);         
	}
      }
    }
  }
}

int main(){
  while(true){
    cin >> w;
    cin >> h;
    count = 0;
    if(w == 0 && h == 0) break;
    LOOP(h,y){
      LOOP(w,x){
	cin >> c[y][x];
      }    
    }
    
    LOOP(h,y){
      LOOP(w,x){
	if(c[y][x] == 1){
	  count++;
	  dfs(y,x);
	}
      }    
    }
    cout << count << endl;
  }
}

C++: #include <iostream>
#include <cstdio>
#include <iomanip>

#include <vector>
#include <map>
#include <set>
#include <queue>
#include <bitset>
#include <stack>
#include <utility>

#include <numeric>
#include <algorithm>
#include <functional>

#include <cctype>

#include <complex>
#include <string>
#include <sstream>

using namespace std;

#define all(c) c.begin(),c.end()
#define rall(c) c.rbegin(),c.rend()
#define rep(i,n) for(unsigned int i=0;i<(n);i++)
#define tr(it,container) for(typeof(container.begin()) it = container.begin(); \
                                                  it != container.end(); ++it)
#define mp(a,b) make_pair((a),(b))

typedef long long ll;
typedef complex<double> P;
const int dx[] = {1,0,-1,0};
const int dy[] = {0,-1,0,1};
const double EPS = 1e-9;
const int days[] = {31,28,31,30,31,30,31,31,30,31,30,31};
const int daysleap[] = {31,29,31,30,31,30,31,31,30,31,30,31};

const int dx2[] = {1,1,1,0,0,0,-1,-1,-1};
const int dy2[] = {1,0,-1,1,0,-1,1,0,-1};

void go(vector<vector<int> > &F,int h,int w){
    if(F[h][w]==0) return;
    F[h][w] = 0;
    for(int i=0;i<9;i++){
        go(F,h+dy2[i],w+dx2[i]);
    }
}
int main(){
    while(true){
        int w,h;
        cin >> w >> h;
        if(w==0) break;
        vector<vector<int> > F(h+2,vector<int>(w+2,0));
        for(int i=1;i<=h;i++){
            for(int j=1;j<=w;j++){
                int x;
                cin >> x;
                F[i][j] = x;
            }
        }
        int c=0;
        for(int i=0;i<h+2;i++){
            for(int j=0;j<w+2;j++){
                if(F[i][j] == 1){
                    go(F,i,j);
                    c++;
                }
            }
        }
        cout << c << endl;
    }
    return 0;
}