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<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<(n);i++)
#define rep2(i,n) for(int i=1;i<=(n);i++)
#define rep3(i,i0,n) for(int i=i0;i<(n);i++)
#define pb push_back
#define mod 1000000007
#define INF 200000000000
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}
#define all(x) x.begin(), x.end()
#define mp make_pair
bool compare(pair<int, int> a, pair<int, int> b) {
    if(a.first != b.first){
        return a.first < b.first;
        
    }else{
        return a.second < b.second;
    }
}
// 入力

vector<vector<ll> > G;
vector<bool> seen;


//ll fcnt=1;
void dfs(ll v){
    seen[v] = 1;

    rep(i,G[v].size()){
        if(seen[G[v][i]] == 0){
            dfs(G[v][i]);
        }
    }

}

int main() {
    
    while(1){
        G.clear();
        seen.clear();
        ll w,h;
    
        cin >> w>>h;
        if(w==0 &&h==0) break;
        ll cnt=1;
        map<pair<ll,ll>,ll> m;
        
        rep(i,h){
            rep(j,w){
                bool c;
                cin >>c;
                if(c){
                    m[mp(i,j)] = cnt;
                    cnt++;
                }
            }
        }
        G.resize(cnt);
        seen.resize(cnt);


        rep(i,h){
            rep(j,w){
                if(m[mp(i,j)]){
                    if(m[mp(i-1,j-1)]){
                        G[m[mp(i,j)]].pb(m[mp(i-1,j-1)]);
                    }
                    if(m[mp(i,j-1)]){
                        G[m[mp(i,j)]].pb(m[mp(i,j-1)]);
                    }
                    if(m[mp(i-1,j)]){
                        G[m[mp(i,j)]].pb(m[mp(i-1,j)]);
                    }
                    if(m[mp(i,j+1)]){
                        G[m[mp(i,j)]].pb(m[mp(i,j+1)]);
                    }
                    if(m[mp(i+1,j)]){
                        G[m[mp(i,j)]].pb(m[mp(i+1,j)]);
                    }
                    if(m[mp(i+1,j-1)]){
                        G[m[mp(i,j)]].pb(m[mp(i+1,j-1)]);
                    }
                    if(m[mp(i-1,j+1)]){
                        G[m[mp(i,j)]].pb(m[mp(i-1,j+1)]);
                    }
                    if(m[mp(i+1,j+1)]){
                        G[m[mp(i,j)]].pb(m[mp(i+1,j+1)]);
                    }

                }
            }
        }
        /*rep(i,G.size()){
            rep(j,G[i].size()){
                cout << G[i][j];
            }
            cout << endl;
        }*/

        /*rep(i,h){
            rep(j,w){
                cout << m[mp(i,j)]<< " ";
            }
            cout << endl;
        }*/
        ll ans = 0;
        rep(i,h){
            rep(j,w){
                if(m[mp(i,j)]){
                    if(seen[m[mp(i,j)]] == 0){
                        dfs(m[mp(i,j)]);
                        ans++;
                    }
                }
            }
        }
        

        cout<<ans<<endl;
    }
    return 0;
    

}

C++: #include "bits/stdc++.h"
using namespace std;

#define rep(i, n) for(auto i=0; i != n; ++i)
#define REP(i, k, n) for(auto i=k; i != n; ++i)
#define rrep(i, n) for(auto i=n; i != 0; --i)
#define RREP(i, n, k) for(auto i=n; i != k; --i)


int sea[60][60];
int w,h;
void dfs(int x, int y){
    int dx[] = {0, 1, -1};
    int dy[] = {0, 1, -1};

    if(sea[x][y] == -1) return ;

    if(sea[x][y] == 1){
        sea[x][y] = -1;
    }

    for(int xx=-1; xx<=1; xx++){
        for(int yy=-1; yy<=1; yy++){
            if(xx==0 && yy==0){
                continue;
            }

            if(sea[x + xx][y + yy] == 1){
                dfs(x+xx, y+yy);

            }

        }
    }



}

int main (){
    while (true){
        cin>>w>>h;
        if(w==0 && h==0){ break;}
        rep(i, 60){
            rep(j,60){
                sea[i][j] = -1;
            }
        }

        rep(i, h){
            rep(j,w){
                cin>>sea[i+1][j+1];
            }
        }


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

        cout<<ans<<endl;

    }

}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int dx[] = {1, 0, -1, 0, 1, 1, -1, -1}, dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
int w, h;

void dfs(int x, int y, vector<vector<int>> &c) {
  if (x < 0 || y < 0 || x >= h || y >= w) {
    return;
  }
  if (c[x][y] == 0) {
    return;  // umi or seeen
  }
  c[x][y] = 0;

  for (int i = 0; i < 8; i++) {
    dfs(x + dx[i], y + dy[i], c);
  }
}
int main() {
  vector<int> ans;
  while (1) {
    cin >> w >> h;
    if (w == 0 && h == 0) {
      break;
    }
    vector<vector<int>> c(h, vector<int>(w));

    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        cin >> c[i][j];
      }
    }
    int count = 0;
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        if (c[i][j] == 1) {
          dfs(i, j, c);
          count++;
        }
      }
    }
    ans.push_back(count);
  }
  for (auto it = ans.begin(); it != ans.end(); it++) {
    cout << *it << endl;
  }
}