Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define FOR(i, m, n) for(ll i = m; i < n; i++)
#define all(vec) vec.begin(), vec.end()
#define tmax(x, y, z) max((x), max((y), (z)))
#define tmin(x, y, z) min((x), min((y), (z)))
ll MM = 1000000000; ll mod = MM + 7; ll MMM=9223372036854775807;//2^63 -1
ll GCD(ll x, ll y){ if(y == 0) return x; else return GCD(y, x % y);}
ll LCM(ll x, ll y){ return x / GCD(x, y) * y;}
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 ll INF = 1LL << 60;
using Graph = vector<vector<ll>>;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int ddx[8] = {1, 1, 0, -1, -1, -1, 0, 1}, ddy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
//cout << fixed << setprecision(10);

int field[100][100];
ll w, h;


void dfs(ll y, ll x){
    field[y][x] = 0;
    rep(i, 8){
        ll ny = y + ddy[i], nx = x + ddx[i];
        if(0 <= ny && ny < h && 0 <= nx && nx < w && field[ny][nx]){
            dfs(ny, nx);
        }
    }
}


int main(){
    vector<ll> res;
    while(1){
        cin >> w >> h;
        if(!w && !h) break;
        rep(hi, h){
            rep(wi, w){
                cin >> field[hi][wi];
            }
        }

        ll ans = 0;
        rep(hi, h){
            rep(wi, w){
                if(field[hi][wi]){
                    dfs(hi, wi);
                    ans++;
                }
            }
        }

        // cout << ans << endl;
        res.push_back(ans);
    }

    rep(i, res.size()) cout << res[i] << endl;
return 0;
}

C++: #include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <cstring>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;
int W, H;
int c[50][50];
bool visited[50][50];
int vy[8] = {-1,-1,0,1,1,1,0,-1};
int vx[8] = {0,1,1,1,0,-1,-1,-1};
void calc(int y, int x) {
  if(y < 0 || y >= H || x < 0 || x >= W) return;
  if(visited[y][x] || c[y][x] == 0) return;
  visited[y][x] = true;
  FOR(i,0,8) calc(y+vy[i],x+vx[i]);
  return;
}
int main()
{
  while(cin >> W >> H, (W || H)) {
    CLR(visited);
    FOR(y,0,H) FOR(x,0,W) cin >> c[y][x];
    int ans = 0;
    FOR(y,0,H) {
      FOR(x,0,W) {
        if(visited[y][x] || c[y][x] == 0) continue;
        calc(y, x);
        ans++;
      }
    }
    cout << ans << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define SORT(c) sort((c).begin(),(c).end())
#define MEMSET(v, h) memset((v), h, sizeof(v))
#define sqr(x) ((x) * (x))
#define bit(n) (1LL<<(n))
#define pcnt(x) __builtin_popcountll(x)
#define PB push_back
#define MP make_pair
#define endl "\n"
using Edge = pair<int,int>;
using Graph = vector<vector<Edge>>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { 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;}

bool visit[60][60];
bool land[60][60];
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};

int w,h; 

bool dfs(int a,int b) {
  if(!visit[a][b] && land[a][b]){
    visit[a][b] = true;
    FOR(i,0,7){
      if(a+dx[i]>=0 && a+dx[i]<=h-1 && b+dy[i]>=0 && b+dy[i]<=w-1 && !visit[a+dx[i]][b+dy[i]] && land[a+dx[i]][b+dy[i]]){
        dfs(a+dx[i],b+dy[i]);
      };
    }
    return true;
  }
  return false;
}

int main() {
  while(1){
    cin >> w >> h;
    if(w==0 && h==0) break;

    FOR(i,0,h-1){
      FOR(j,0,w-1){
        int c; cin >> c;
        visit[i][j] = false;
        land[i][j] = c;
      }
    }

    int ans = 0;

    FOR(i,0,h-1){
      FOR(j,0,w-1){
        int track = ans;
        ans += dfs(i,j);
        // if(track!=ans) cout << i << " " << j << endl;
      }
    }
    cout << ans << endl;
  }

  


}

C++: #include <iostream>
#include <deque>
#include <cstring>
#include <algorithm>

using namespace std;

int dx[8] = {-1,-1,-1,0,0,1,1,1};
int dy[8] = {-1,0,1,-1,1,-1,0,1};

int main(){
    int n,m;
    while(cin >> m >> n){
        if((n|m) == 0) break;
        bool field[n+2][m+2];
        bool visited[n+2][m+2];
        deque<pair<int,int> > q;
        int tmp;
        int ret = 0;

        memset(field, false, sizeof(field));
        memset(visited, false, sizeof(visited));
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                cin >> tmp;
                field[i][j] = tmp?true:false;
            }
        }
        for(int i=1;i<=n;i++){
            for(int j=1;j<=m;j++){
                if(visited[i][j] == false && field[i][j] == true){
                    q.push_back(make_pair(i,j));
                    ret++;
                }
                while(!q.empty()){
                    int x = q.front().first;
                    int y = q.front().second;
                    q.pop_front();
                    if(visited[x][y] == true){
                        continue;
                    }else{
                        visited[x][y] = true;
                    }
                    for(int k=0;k<8;k++){
                        if(field[x+dx[k]][y+dy[k]] == true &&
                           visited[x+dx[k]][y+dy[k]] == false){
                            q.push_back(make_pair(x+dx[k], y+dy[k]));
                        }
                    }
                }
            }
        }
        cout << ret << endl;
    }
}

C++: #include <cstdio>
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;
int dx[8]={1,1,1 ,0, 0,-1,-1,-1};
int dy[8]={0,1,-1,1,-1, 1, 0,-1};
int c[55][55];
int w,h;
int res;
void paint(int i,int j,int k){
  if(i<0||j<0)return;
  else if(i>=h||j>=w) return;
  else if(c[i][j]!=1) return;
  c[i][j]=k;
  for(int l=0;l<8;l++) paint(i+dx[l],j+dy[l],k);
  return;
}
void count(int i,int j){
  res++;
  paint(i,j,res);
  return;
}
int main(void){
  int i,j;
  while(scanf("%d %d",&w,&h),w|h){
    res=1;
    for(i=0;i<h;i++){
      for(j=0;j<w;j++){
        scanf("%d",&c[i][j]);
      }
    }
    for(i=0;i<h;i++){
      for(j=0;j<w;j++){
        if(c[i][j]==1){
          count(i,j);
        }
      }
    }
    printf("%d\n",res-1);
  }
  return 0;
}