Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<vector>
#include<list>

int history[50][50];
int w,h;
int cnt;

using namespace std;

int search_map(int x,int y,int flag_new,int m[50][50]){

  if(!(x>=0 && x<w && y>=0 && y<h)) return 0;

  if(history[y][x] == 1) return 0;
  else{
    history[y][x]=1;

    if(m[y][x]){

      if(flag_new) cnt++;

      for(int i=-1 ; i<2;i++){
        for(int j=-1 ; j<2;j++){
          if(i==0 && j==0) continue;
          search_map(x+i,y+j,0,m);
        }
      }

    }
    else{
      return 0;
    }

  }

}

int main(void){

  int map[50][50];

  for(cin>>w,cin>>h;w>0 && h>0;cin>>w,cin>>h){
    cnt=0;
    for(int i=0;i<50;i++){
      for(int j=0;j<50;j++){
        history[i][j]=0;
      }
    }
    //cout << w << "," << h << endl;
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        cin >> map[i][j];
        //cout << map[i][j] << " ";
      }
      //cout << endl;
    }

    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
        search_map(j,i,1,map);
        //cout << map[i][j] << " ";
      }
      //cout << endl;
    }
    cout << cnt << endl;
  }

  return 0;
}

C++: #include <iostream>

using namespace std;
int c[51][51];
int w ,h;

bool input(){
	cin >> h >> w;
	if(w==0) return false;
	for(int i = 0;i <51;i++){
		for(int j = 0;j <51 ;j++){
			c[i][j] = 2;
		}
	}

	for(int i = 0;i < w ;i++){
		for(int j = 0; j < h ;j++){
			cin >> c[i][j];
//			cout <<c[i][j];
		}
	}
	return true;
}

void dfs(int x,int y){
	c[x][y] = 0;
	for(int i = -1; i <=1 ;i++){
		for(int j = -1; j <=1 ;j++){
			int nx = x + i;
			int ny = y + j;
//			cout <<nx << ' ' << ny << endl;
			if(0 <= nx && nx < w && 0 <= ny && ny < h && c[nx][ny] == 1)dfs(nx,ny);
		}
	}
}

void solve(){
	int res = 0;
/*	for(int i=0;i < w ;i++){
		for (int j=0;j<h;j++){
			cout <<c[i][j];
		}
		cout <<endl;
	}
*/
	for(int i=0; i < h;i++){
		for(int  j=0;j < w;j++){
			if(c[i][j] ==1){
				res++;
				dfs(i,j);
			}
		}
	}
	cout << res << endl;
}

int main(){
	while(input())solve();
}

C++: #include<bits/stdc++.h>
#define rep(i,n) for(int i=0; i<n; i++)
using namespace std;
int table[105][105];
int check(int i, int j){
  for(int a=i-1; a<i+2; a++){
    for(int b=j-1; b<j+2; b++){
      if(table[a][b]==1){
        table[a][b]=0;
        check(a,b);
      }
    }
  }
  return 0;
}
int main(){
  int w,h;
  while(1){
    cin >> w >> h;
    if(w==0 && h==0) break;
    table[w+2][h+2]={};
    rep(i,h) rep(j,w) cin >> table[i+1][j+1];
    rep(i,h+1){
      rep(j,w+1){
        if(table[i][j]==1){
          table[i][j]=2;
          check(i,j);
        }
      }
    }
    int count=0;
    for(int i=1; i<h+1; i++) for(int j=1; j<w+1; j++) if(table[i][j]==2) count++;
    cout << count << endl;
    rep(i,h+2){
      rep(j,w+2) cout << table[i][j] << " ";
      cout << endl;
    }
  }
  return 0;
}

C++: #include <iostream>
#include <queue>
#include <map>
#include <cmath>
#include <algorithm>
#include <queue>
#include <cstdarg>

using namespace std;
#define INF 2e9 + 9
#define ALL(v) v.begin() , v.end()
#define Int int64_t
#define pll pair<Int,Int>
template<class T> using pql = priority_queue<T, vector<T>>;
template<class T> using pq = priority_queue<T, vector<T>, greater<T>>;
#define ll(n) Int n; cin >> n;
#define LL(...) Int __VA_ARGS___; cin >> __VA_ARGS___;
#define OUT(...) cout << __VA_ARGS___;
#define RP(n, i, s) for(Int i = s ;i < n ;i++)
#define REP(n, i) for (Int i = 0; i < n; i++)
#define REPe(n, i) for (Int i = 1; i <= n; i++)
#define RPe(n, i, s) for (Int i = s; i <= n; i++)
#define upd_max(maxer, updater) if (maxer < updater) maxer = updater;

struct node {
    Int to;
    Int length;
};


vector<Int> divisor(Int n) {
    vector<Int> ret;
    for (Int i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ret.push_back(i);
            if (i * i != n) ret.push_back(n / i);
        }
    }
    return (ret);
}


vector<vector<int>> to;
vector<int> flag;
vector<int> c;

Int dfs(int from, int mae) {
    flag[from] = 1;
    Int mini = 0;
    for (auto next : to[from]) {
        if (next == mae) continue;
        if (flag[next] == 1) {
            return -1;
        } else {
            mini = min(mini, dfs(next, from));
        }
    }
    return mini;
}

int dx8[8] = {0, -1, -1, -1, 0, 1, 1, 1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};

vector<vector<Int>> a;
vector<vector<Int>> d;
Int w, h;

void dfs(int x, int y, int id) {
    if (d[y][x] != 0) return;
    d[y][x] = id;
    REP(8, i) {
        Int tox = x + dx8[i];
        Int toy = y + dy8[i];
        if (tox >= 0 && toy >= 0 && tox < w && toy < h && a[toy][tox] == 1) {
            a[toy][tox] = 0;
            dfs(tox, toy, id);
        }
    }
}


int main(void) {
    while (true) {
        cin >> w >> h;
        if (w == 0) break;
        d.assign(h, vector<Int>(w, 0));
        a.clear();
        REP(h, i) {
            vector<Int> z;
            REP(w, k) {
                Int tmp;
                cin >> tmp;
                z.push_back(tmp);
            }
            a.push_back(z);
        }
        Int cnt = 1;
        // a[y][x]

        REP(h, k) {
            REP(w, i) {
                if (a[k][i] == 1) dfs(i, k, cnt);
                /*for (auto z : a){
                cout << "Cnt : " << cnt << endl;
                    for (auto zz : z){
                        cout << zz << " ";
                    }
                    cout << endl;
                }*/
                cnt++;
            }
        }
        map<int, int> mp;
        REP(h, k) {
            REP(w, i) {
                if (d[k][i] != 0) mp[d[k][i]]++;
            }
        }
        cout << mp.size() << endl;
    }
}