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 <algorithm>
#include <cmath>
#include <climits>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <cassert>

using namespace std;

#define LOG(...) printf(__VA_ARGS__)
//#define LOG(...)
#define FOR(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define RSORT(c) sort((c).rbegin(),(c).rend())
#define CLR(a) memset((a), 0 ,sizeof(a))

typedef long long ll;
typedef unsigned long long ull;
typedef vector<bool> vb;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vb> vvb;
typedef vector<vi> vvi;
typedef vector<vll> vvll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

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

const int L_MAP = 50;
bool field[L_MAP + 2][L_MAP + 2];

const bool LAND = true;
const bool SEA = false;

void dfs(int x, int y){
    if(field[y][x] == SEA)
        return;

    field[y][x] = SEA;
    FOR(dy, -1, 1 + 1){
        FOR(dx, -1, 1 + 1){
            dfs(x+ dx, y + dy);
        }
    }
}

int main() {
    int w, h;
    while(cin >> w >> h, w|h){
        fill_n((bool *)field, (L_MAP + 2) * (L_MAP + 2), SEA);
        REP(y, h){
            REP(x, w) {
                cin >> field[y][x];
            }
        }

        int cnt = 0;
        REP(y, h + 1) {
            REP(x, w + 1) {
                if (field[y][x] == LAND) {
                    dfs(x, y);
                    cnt ++;
                }
            }
        }

        cout << cnt << endl;
    }

}

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

typedef long long ll;
using namespace std;

int H, W;
vector<vector<int> > C;
vector<vector<int> > visited;
int ans = 0;





void dfs(int &i, int &j){
    visited[i][j] = 1;
    for(int y=-1; y<=1; y++){
        for(int x=-1; x<=1; x++){
            int ny = i+y;
            int nx = j+x;
            
            if(ny>=0 && ny<H && nx>=0 && nx<W && C[ny][nx] && !visited[ny][nx]) dfs(ny, nx);
        }
    }
    return;
}




int main() {
    while(1){
        ans = 0;
        visited.clear();
        
        cin >> W >> H; if((W&H)==0) break;
        C.resize(H);
        for(vector<int> &v:C) v.resize(W);
        for(vector<int> &row:C)
            for(int &c:row) cin >> c;

        visited.resize(H);
        for(vector<int> &v:visited) v.resize(W);

        for(int i=0; i<H; i++){
            for(int j=0; j<W; j++){
                if(C[i][j] && !visited[i][j]){
                    dfs(i,j);
                    ans ++;
                }
            }
        }
        
        
        cout << ans << endl;
    }
    return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

#define int long long

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

void DFS(int x, int y, int fld[50][50])
{
	if (fld[y][x] == 0) return;
	fld[y][x] = 0;
	for (int i = 0; i < 8; i++)
	{
		int nx = x + dx[i], ny = y + dy[i];
		if (nx < 0 || W <= nx || ny < 0 || H <= ny) continue;
		DFS(nx, ny, fld);
	}
}

signed main()
{
	while (cin >> W >> H, W || H)
	{
		int fld[50][50];
		for (int i = 0; i < H; i++)
		{
			for (int j = 0; j < W; j++)
			{
				cin >> fld[i][j];
			}
		}

		int cnt = 0;
		for (int i = 0; i < H; i++)
		{
			for (int j = 0; j < W; j++)
			{
				if (fld[i][j] == 1) cnt++;
				DFS(j, i, fld);
			}
		}
		printf("%lld\n", cnt);
	}
}

C++: #include <iostream>
 
using namespace std;
int field[50][50];
int w, h, ans;
int dx[8] = {-1, 0, 1, -1, 1, -1, 0, 1}, dy[8] = {-1, -1, -1, 0,  0, 1, 1, 1};
 
void check(int x, int y)
{
    if (field[x][y])
        field[x][y] = 0;
    else
        return;
         
    for (int i=0; i<8; i++) {
        int nx = x+dx[i], ny = y+dy[i];
        if (0<= nx && nx<w && 0<=ny&&ny<h) {
            check(nx, ny);
        }
    }
}
 
int main()
{
    while (cin>>w>>h, w||h) {
        for (int y=0; y<h; y++) {
            for (int x=0; x<w; x++) {
                int i; cin >> i;
                field[x][y] = i;
                }
           }
        
       ans = 0;
       for (int y=0; y<h; y++) {
          for (int x=0; x<w; x++) {
               if (field[x][y]) {
                       ans++;
                       check(x, y);
               }  
            }   
        }
 
        cout << ans << endl;
   }           
     
    return 0;
}