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>
#define rep(i, a, b) for (int i = a; i < (b); i++)
#define rrep(i, a, b) for (int i = a; i >= (b); i--)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
using P = pair<int, int>;
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 = 2e9;
const int MOD = 1e9 + 7;

int main() {
   while (true) {
      int w, h;
      cin >> w >> h;
      if (w == 0 && h == 0) break;
      vector<vector<int>> c(h, vector<int>(w)), a(h, vector<int>(w));

      rep(i, 0, h) rep(j, 0, w) cin >> c[i][j];
      int ans = 0;
      function<void(int, int)> dfs = [&](int u, int v) {
         if (a[v][u] != 0) return;
         c[v][u] = ans;
         a[v][u] = 1;
         rep(i, -1, 2) rep(j, -1, 2) {
            int x_i = u + i;
            int y_j = v + j;
            if (x_i >= 0 && x_i < w && y_j >= 0 && y_j < h && c[y_j][x_i] == 1)
               dfs(x_i, y_j);
         }
         return;
      };
      rep(i, 0, h) {
         rep(j, 0, w) {
            if (a[i][j] == 0 && c[i][j] == 1) {
               ans++;
               dfs(j, i);
            }
         }
      }
      cout << ans << endl;
   }
   return 0;
}

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

using namespace std;

inline bool inRange(int a, int x, int b) {
    return a <= x && x < b;
}

void fill(vector<vector<int> > &v, int r, int c) {
    queue<pair<int,int> > q;
    q.push(make_pair(r, c));
    v[r][c] = 0;
    while(!q.empty()) {
        const pair<int,int> cur = q.front();
        q.pop();
        for(int dr = -1; dr <= 1; ++dr) {
            for(int dc = -1; dc <= 1; ++dc) {
                int nr = cur.first + dr;
                int nc = cur.second + dc;
                if(inRange(0, nr, v.size()) && 
                   inRange(0, nc, v[0].size()) &&
                   v[nr][nc])
                {
                    v[nr][nc] = 0;
                    q.push(make_pair(nr, nc))
                }
            }
        }
    }
}

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

    while(true) {
        int C, R;
        cin >> C >> R;
        if(!C && !R) break;

        vector<vector<int> > v(R, vector<int>(C));
        for(int i = 0; i < R; ++i) 
            for(int j = 0; j < C; ++j)
                cin >> v[i][j];

        int cnt = 0;
        for(int r = 0; r < R; ++r) {
            for(int c = 0; c < C; ++c) {
                if(v[r][c]) {
                    ++cnt;
                    fill(v, r, c);
                }
            }
        }

        cout << cnt << endl;
    }

    return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<algorithm>

#define rep(i,n) for(int i=0;i<(n);i++)

using namespace std;

int map[51][51];
int w,h;

void dfs(int x,int y) {
	map[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;
			if(0<=nx&&nx<w && 0<=ny&&ny<h && map[nx][ny]==1)
				dfs(nx,ny);
		}
	}


}

void solve() {
	rep(i,51) rep(j,51) map[i][j]=0;

	rep(i,w) rep(j,h) cin>>map[i][j];

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

int main() {

	while (cin>>h>>w)
	{
		if(h+w==0) return 0;
		solve();

	}

	return 0;
}

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

#define iota(i,n,b,s) for(int i=int(b);i!=int((b)+(s)*(n));i+=(s))
#define range(i,n,m) iota(i,(((n)>(m))?((n)-(m)):((m)-(n))),(n),((n)>(m)?-1:1))
#define rep(i,n) iota(i,(n),0,1)
#define loop for(;;)

#define INF (1e9)
#define EPS (1e-9)
#define cons(a,b) (make_pair(a,b))
#define car(a) (a.first)
#define cdr(a) (a.second)
#define cadr(a) (car(cdr(a)))
#define cddr(a) (cdr(cdr(a)))
#define all(a) a.begin(), a.end()
#define trace(var) cerr<<">>> "<<#var<<" = "<<var<<endl;

typedef long long Integer;
typedef double Real;
typedef vector<int> vi;
typedef vector<string> vs;
typedef map<string,int> Dictionary;
const Real PI = acos(-1);

template<class S, class T>
ostream& operator<<(ostream& os, pair<S,T> p) {
  os << '(' << car(p) << ", " << cdr(p) << ')';
  return os;
}

template<class T>
ostream& operator<<(ostream& os, vector<T> v) {
  if (v.size() == 0) {
    os << "(empty)";
    return os;
  }
  os << v[0];
  for (int i=1, len=v.size(); i<len; ++i) os << ' ' << v[i];
  return os;
}

int dx[] = { -1, 0, 1, 0 };
int dy[] = {  0, -1, 0, 1 };

int main() {

  for (int w,h; cin >> w >> h, w && h; ) {
    vector<vector<int>> f(h, vector<int>(w));
    rep (i, h) {
      rep (j, w) {
        cin >> f[i][j];
      }}
    int cx = 0;
    rep (i, h) {
      rep (j, w) {
        if (f[i][j] == 0) continue;
        ++cx;

    stack<pair<int, int>> s;
    s.push(cons(i, j));

    while (!s.empty()) {
      auto x = s.top(); s.pop();
      if (car(x) < 0) continue;
      if (car(x) >= h) continue;
      if (cdr(x) < 0) continue;
      if (cdr(x) >= w) continue;
      if (f[car(x)][cdr(x)] == 0) continue;

      f[car(x)][cdr(x)] = 0;

      s.push(cons(car(x) + 1, cdr(x)));
      s.push(cons(car(x) - 1, cdr(x)));
      s.push(cons(car(x), cdr(x) + 1));
      s.push(cons(car(x), cdr(x) - 1));
      s.push(cons(car(x) + 1, cdr(x) - 1));
      s.push(cons(car(x) - 1, cdr(x) + 1));
      s.push(cons(car(x) + 1, cdr(x) + 1));
      s.push(cons(car(x) - 1, cdr(x) - 1));
    }

      }}

    cout << cx << endl;

  }
  return 0;
}