Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var route [][]int

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(h, w int) {
	if route[h][w] == 0 {
		return
	}

	route[h][w] = 0
	for _, x := range []int{-1, 0, 1} {
		for _, y := range []int{-1, 0, 1} {
			if route[h+x][w+y] == 0 {
				continue
			}
			dfs(h+x, w+y)
		}
	}
}

func main() {
	writer := bufio.NewWriter(os.Stdout)
	for {
		w, h := scanInt(), scanInt()
		if w == 0 && h == 0 {
			break
		}

		route = make([][]int, h+2)
		route[0] = make([]int, w+2)
		for i := 1; i <= h; i++ {
			route[i] = make([]int, w+2)
			for j := 1; j <= w; j++ {
				route[i][j] = scanInt()
			}
		}
		route[h+1] = make([]int, w+2)

		total := 0
		for i := 1; i <= h; i++ {
			for j := 1; j <= w; j++ {
				if route[i][j] == 1 {
					total++
					dfs(i, j)
				}
			}
		}
		fmt.Fprintln(writer, total)
	}
	writer.Flush()
}

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

#define W 50
#define H 50

using namespace std;
void dfs(int w, int h);
int map[H][W];
int dy[8] = {1,1,0,-1,-1,-1,0,1}, dx[8] = {0,-1,-1,-1,0,1,1,1};
int w,h;

int main(){
  int i = 0,j = 0,is=0;
  cin >> w >> h;

  while(w != 0 && h != 0){
    for(i = 0;i < h;i++){
      for(j = 0;j<w;j++){
	cin>>map[i][j];
      }
    }
    i = j = 0;
    is = 0;
    while(i <= h-1  && j <= w-1){
      if(map[i][j] == 1){
	dfs(i,j);
	cout << "dfs end" << endl;
	is++;
      }
      i++;
      if(i == h){
	i = 0;
	j++;
      }
    }
    cout <<"the number of island is " << is << endl;
    cin >> w >> h;
  }
  return 0;
}

void dfs(int x,int y){
  cout << "x is " << x << " y is " << y <<endl;
  int i = 0;
  map[x][y] = 0;
  for(i = 0;i < 8; i++){
    if(x + dx[i] > -1 && y + dy[i] > -1 && x + dx[i] < h && y + dy[i] < w){
      if(map[x + dx[i]][y + dy[i]] == 1){
	dfs(x + dx[i],y + dy[i]);
      }
    }
  }
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<cctype>
#include<climits>
#include<bitset>
#define ld long double
#define ll long long int
#define ull unsigned long long int
#define rep(i,n) for(i=0;i<n;i++)
#define fin(ans) cout<<(ans)<<endl
#define INF INT_MAX
#define vi vector<int>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pair<int,int> >
#define vvi vector<vector<int> >
#define vvc vector<vector<char> >
#define vvs vector<vector<string> >
#define P 1000000007
using namespace std;
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;}
const long long LLINF=1LL<<60;
//set<int>::iterator it;
//|\_
//g++ -std=c++1z temp.cpp
//./a.out

vvi v(50,vi(50,-2));

bool dfs(int x,int y,int count,int h,int w){
    
    if(v[y][x]>=0)return false;
    v[y][x]=count;
    bool t=true;
    if(x+1<w&&v[y][x+1]==-1){
        t=dfs(x+1,y,count,h,w);
    }
    if(x-1>=0&&v[y][x-1]==-1){
        t=dfs(x-1,y,count,h,w);
    }
    if(y+1<h&&v[y+1][x]==-1){
        t=dfs(x,y+1,count,h,w);
    }
    if(y-1>=0&&v[y-1][x]==-1){
        t=dfs(x,y-1,count,h,w);
    }///////
    if(x+1<w&&y+1<h&&v[y+1][x+1]==-1){
        t=dfs(x+1,y+1,count,h,w);
    }
    if(x-1>=0&&y-1>=0&&v[y-1][x-1]==-1){
        t=dfs(x-1,y-1,count,h,w);
    }
    if(y+1<h&&x-1>=0&&v[y+1][x-1]==-1){
        t=dfs(x-1,y+1,count,h,w);
    }
    if(y-1>=0&&x+1<w&&v[y-1][x+1]==-1){
        t=dfs(x+1,y-1,count,h,w);
    }
    if(t) return true;
    else return false;
}

int main(void){ios::sync_with_stdio(false);cin.tie(0);
//////////////////////////////////////////////////////
    int w,h,i,j;
    while(1){
        cin>>w>>h;
        if(w==0&&h==0)break;
        int count=1,x,y;
        rep(i,50)rep(j,50)v[i][j]=-2;
        rep(i,h)rep(j,w){
            cin>>v[i][j];
            v[i][j]*=-1;
        }
        bool c;
        for(y=0;y<h;y++){
            for(x=0;x<w;x++){
                c=dfs(x,y,count,h,w);
                if(c)count++;
            }
        }
        set<int> s;
        for(y=0;y<h;y++){
            for(x=0;x<w;x++){
                if(v[y][x]>0)s.insert(v[y][x]);
            }
        }
        cout<<s.size()<<endl;
        /*
        for(y=0;y<h;y++){
            for(x=0;x<w;x++){
                cout<<v[y][x]<<" ";
            }
            cout<<endl;
        }*/
    }
    

//////////////////////////////////////////////////////
return 0;}