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<iostream>
#include<vector>
using namespace std;
int needx[]={-1,0,1,0,1,1,-1,-1};
int needy[]={0,1,0,-1,1,-1,1,-1};
//??¶?????¨???false????????????true???????????¢??°//
bool land(int x,int y,vector<vector<bool> >& cango){
    if(cango[x][y]){
        cango[x][y]=false;
        for(int i=0;i<8;i++){
            int nextx=x+needx[i];
            int nexty=y+needy[i];
            if(cango[nextx][nexty])
                bool flag=land(nextx,nexty,cango);
            }
    return true;
     }else{
return false;
    }
}
int main(void){
    int input;
	int w,h;
	while(1){
cin>>w>>h;
if(h==0)break;
    vector<vector<bool> > cango(h+2,vector<bool>(w+2,false));
    for(int i=1;i<=h;i++){
        for(int j=1;j<=w;j++){
            cin >>input;
            if(input==1){
cango[i][j]=true;
            }
        }
    }
  
    int t=0;
for(int i=1;i<=h;i++){
    for(int j=1;j<=w;j++){
        if(land(i,j,cango)){
            t++;
        }
    }
}
cout <<t<<endl;
	}
return 0;
}

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

const int MAXH = 50;
const int MAXW = 50;
int W, H;
int G[MAXH][MAXW];

int dfs(int x, int y) {
  const static int dx[] = {1,0,-1,0,1,1,-1,-1};
  const static int dy[] = {0,1,0,-1,1,-1,1,-1};
  G[y][x] = 0;
  int res = 1;
  for(int k = 0; k < 8; ++k) {
    int nx = x + dx[k];
    int ny = y + dy[k];
    if(nx < 0 || nx >= W) continue;
    if(ny < 0 || ny >= H) continue;
    if(G[ny][nx] == 0) continue;
    res += dfs(nx, ny);
  }
  return res;
}

int main() {
  for(; cin >> W >> H && (W|H);) {
    int sx, sy;
    for(int i = 0; i < H; ++i) {
      for(int j = 0; j < W; ++j) {
        cin >> G[i][j];
      }
    }
    int res = 0;
    for(int i = 0; i < H; ++i) {
      for(int j = 0; j < W; ++j) {
        if(G[i][j]) {
          dfs(j, i);
          ++res;
        }
      }
    }
    cout << res << endl;
  }
  return 0;
}

C++: #include<iostream>
using namespace std;
#include<vector>

int wm,hm;
vector< vector<int> > wh(50, vector<int>(50,0));

int xp[]={-1,0,1,-1,1,-1,0,1};
int yp[]={-1,-1,-1,0,0,1,1,1};

void dfs(int x,int y){
  for(int i=0;i<8;i++){
    int nx=x+xp[i];
    int ny=y+yp[i];
    if(nx>-1&&nx<wm&&ny>-1&&ny<hm&&wh[nx][ny]==1){
      //cout<<nx<<" "<<ny<<" "<<wh[nx][ny]<<endl;
      wh[nx][ny]=0;
      dfs(nx,ny);
    }
  }
}

int main(){
  while(1){
    //int wm,hm;
    int aa,bb;
    cin>>aa>>bb;
    wm=bb;
    hm=aa;
    if(wm==0&&hm==0)break;
    //vector< vector<int> > wh(wm, vector<int>(hm));
    for(int i=0;i<wm;i++){
      for(int j=0;j<hm;j++){
        int a;
        cin>>a;
        wh[i][j]=a;
      }
    }
    int ans=0;
    for(int i=0;i<hm;i++){
      for(int j=0;j<wm;j++){
        if(wh[i][j]==1){
          //cout<<"*"<<i<<" "<<j<<endl;
          wh[i][j]=0;
          dfs(i,j);
          ans++;
        }
      }
    }
    cout<<ans<<endl;
  }
  return 0;
}

C++: #include <iostream>

using namespace std;

int m[51][51];
int w, h;
const int dx[] = {-1, 0, 1, -1, 1, -1, 0, 1};
const int dy[] = {-1, -1, -1, 0, 0, 1, 1, 1};

void dfs(int x, int y)
{
    m[y][x] = 0;
    for (int i = 0; i < 8; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        
        if (nx < 0 || ny < 0 || nx >= w || ny >= h)
            continue;
        else if (m[ny][nx] == 1)
            dfs(nx, ny);
    }
}

int main()
{
    while (cin >> w >> h, w || h) {
        int isl = 0;

        for (int i = 0; i < h; i++)
            for (int j = 0; j < w; j++)
                cin >> m[i][j];

        for (int i = 0; i < h; i++) 
            for (int j = 0; j < w; j++)
                if (m[i][j] == 1) {
                    dfs(i, j);
                    isl++;
                }

        cout << isl << endl;
    }

    return 0;
}

C++: #include <cstdio>

using namespace std;

int w, h;
int field[50][51];

void dfs(int x, int y)
{
	field[x][y] = 0;
	
	for(int dx = -1; dx <= 1; dx++){
		for(int dy = -1; dy <= 1; dy++){
			int nx = x + dx;
			int ny = y + dy;
			
			if(0 <= nx && nx < w && 0 <= ny && ny < h && field[nx][ny] == 1) dfs(nx, ny);
		}
	}
	return ;
}

void solve(void){
	int res = 0;
	for(int i = 0; i < h; i++){
		for(int j = 0; j < w; j++){
			if(field[i][j] == 1){
				dfs(i, j);
				res++;
			}
		}
	}
	printf("%d\n", res);
}

int main(void)
{
	while(scanf("%d %d", &w, &h) != EOF){
		if(w == 0 && h == 0){ break; }
		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				scanf("%d", &field[i][j]);
			}
		}
		solve();
	}
	
	return 0;
}