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 <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <cstring>
#include <climits>
#include <cmath>
#include <cfloat>

#define FOR(i,b,n) for(int i=b;i<n;i++)
#define CLR(mat) memset(mat, 0, sizeof(mat))

using namespace std;

bool field[51][51];
int w, h, cnt;
int dx[] = { 1, 0, 0, -1, 1, -1, -1, 1}, dy[] = {0, 1, -1, 0, 1, 1, -1, -1};



void rec(int x, int y)
{
	if( x >= 0 && x < w && y >= 0 && y < h && field[y][x] == 1)
	{
		field[y][x] = 0;
	
		FOR(i, 0, 8)
			rec(x+dx[i], y+dy[i]);
	}
	return;
}



int main()
{
	while( cin >> w >> h, (w||h))
	{
		cnt = 0;
		
		FOR(j, 0, h)
			FOR(i, 0, w)
				cin >> field[j][i];
		
		FOR(j, 0, h)
			FOR(i, 0, w)
			{
				if( field[j][i] == 1)
					cnt++;
					rec(i, j);
			}
		
		
		cout << cnt << endl;
	}
	
	return 0;
}

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

using namespace std;

int w,h;
int g[51][51];
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void dfs(int x,int y){
  g[y][x]=0;
  for(int i=0;i<4;i++){
    int nx=x+dx[i],ny=y+dy[i];
    if(0<=nx && nx<w && 0<=ny && ny<h && g[ny][nx]==1)
      dfs(nx,ny);
  }
}

int main(void){

  while(cin >> w >> h, w|h){
    for(int i=0;i<h;i++)
      for(int j=0;j<w;j++)cin >> g[i][j];

    int cnt=0;
    for(int i=0;i<h;i++)
      for(int j=0;j<w;j++)
	if(g[i][j]==1)cnt++,dfs(j,i);

    cout << cnt << endl;
  }
  
  return 0;
}

C++: #include <iostream>
using namespace std;
int map[51][51],w,h;
void dfs(int y,int x){
	map[y][x] = 0;
	int tx,ty;
	for(int dx=-1;dx<=1;dx++){
		for(int dy=-1;dy<=1;dy++){
			tx = x + dx;
			ty = y + dy;
			if(tx > -1 && tx < w && ty > -1 && ty < h && map[ty][tx] == 1) dfs(ty,tx);
		}
	}
	return;

}
int main(){
	int count;
	while(cin >> w >> h && (w!=0 && h!=0)){
		count = 0;
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				cin >> map[i][j];
			}
		}
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				if(map[i][j] == 1){
					dfs(i,j);
					count++;
				}
			}
		}
		cout << count << endl;
	}
	return 0;
}

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

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

void dfs(int x, int y, vector<vector<bool> >& canGo){
  canGo[x][y] = false;
  for(int i = 0; i < 9; i++)
    if(canGo[x + dx[i]][y + dy[i]])
      dfs(x + dx[i], y + dy[i], canGo);
  return;
}


int main(void){
  while(true){
    int w, h;
    cin >> w >> h;
    if(w == 0 && h == 0){ break; }

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

    cout << count << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int ans = 1e9;
int H,W;
int mp[52][52];
int nx,ny;
void func(int y,int x){
	//cout << y << ' ' <<x<<endl;
	if(mp[y][x] == 1){
		mp[y][x] = 2;
		func(y,x);
	}
	if(mp[y+1][x] == 1){
		mp[y+1][x] = 2;
		func(y+1,x);
	}
	if(mp[y][x+1] == 1){
		mp[y][x+1] = 2;
		func(y,x+1);
	}
	if(mp[y+1][x+1] == 1){
		mp[y+1][x+1] = 2;
		func(y+1,x+1);
	}
	if(mp[y-1][x] == 1){
		mp[y-1][x] = 2;
		func(y-1,x);
	}
	if(mp[y][x-1] == 1){
		mp[y][x-1] = 2;
		func(y,x-1);
	}
	if(mp[y-1][x-1] == 1){
		mp[y-1][x-1] = 2;
		func(y-1,x-1);
	}
	if(mp[y+1][x-1] == 1){
		mp[y+1][x-1] = 2;
		func(y+1,x-1);
	}
	if(mp[y-1][x+1] == 1){
		mp[y-1][x+1] = 2;
		func(y-1,x+1);
	}
}
void findL(){
	nx = -1;ny = -1;
	for(int i = 1; i <= H; i++){
		for(int j = 1; j <= W; j++){
			if(mp[i][j] == 1){
				nx = j,ny = i;
				//cout <<nx<<ny<<endl;
				i = H; j = W;
			}
		}
	}
}
int main(){
	cin >> H>>W;
	while(W!=0||H!=0){
		for(int i = 0; i < 52;i++){
			for(int j = 0; j < 52; j++){
				mp[i][j] = 0;
			}
		}
		for(int i = 1; i <= H; i++){
			for(int j = 1; j <= W; j++){
				cin >> mp[i][j];
			}
		}
		int c = 0;
		findL();
		while(nx != -1 && ny != -1){
			func(ny,nx);
			c++;
			findL();
		}
		cout << c << endl;
		cin >> W >> H;
	}
	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[x][y] = 0;
    for (int i = 0; i < 8; i++) {
        int nx = x + dx[i];
        int ny = y + dy[i];
        
        if (nx < 0 || ny < 0 || nx >= h || ny >= w)
            continue;
        else if (m[nx][ny] == 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;
}