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<fstream>

using namespace std;

	ifstream fin;
	ofstream fout;

	//http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160&lang=jp

	int gomi = 0;

	int a[52][52] = {};
	int check(int, int);

	int main(){

		fin.open("input.txt");
		fout.open("output.txt");

		//		int w = 0, h = 0;
		int width = 0, height = 0;
		int count = 0;


		while (1){
			for (int i = 0; i < 50; i++)
				for (int j = 0; j < 50; j++)
					a[i + 1][j + 1] = 0;

			cin >> width >> height;
			if (width == 0 && height == 0)break;

			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					//初期化
					gomi = a[i + 1][j + 1] = 0;

					cin >> a[i + 1][j + 1];
				}
			}

			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					if (a[i + 1][j + 1] == 1){
						check(i + 1, j + 1);
//						a[i + 1][j + 1] = 1;
						count++;
					//	cout << i + 1 << "  " << j + 1 << endl;
					}
				}
			}
//			cout << count << endl;
			fout << count << endl;

			//初期化
			count = 0;
			for (int i = 0; i < height; i++){
				for (int j = 0; j < width; j++){
					a[i + 1][j + 1] = 0;
				}
			}
		}
	}

	int check(int y, int x){
		for (int i = -1; i <= 1; i++)
			for (int j = -1; j <= 1; j++)
				check(y + i, x + j);
	return 0;
	}

/*	int check(int y, int x){
		if (a[y + 1][x] == 1){
			a[y + 1][x] = 0;
			check(y + 1, x);
		}
		//-----------------------------
		if (a[y][x + 1] == 1){
			a[y][x + 1] = 0;
			check(y, x + 1);
		}
		//-----------------------------
		if (a[y - 1][x] == 1){
			a[y - 1][x] = 0;
			check(y - 1, x);
		}
		//-----------------------------
		if (a[y][x - 1] == 1){
			a[y][x - 1] = 0;
			check(y, x - 1);
		}
		//-----------------------------
		if (a[y + 1][x + 1] == 1){
			a[y + 1][x + 1] = 0;
			check(y + 1, x + 1);
		}
		//-----------------------------
		if (a[y + 1][x - 1] == 1){
			a[y + 1][x - 1] = 0;
			check(y + 1, x - 1);
		}
		//-----------------------------
		if (a[y - 1][x + 1] == 1){
			a[y - 1][x + 1] = 0;
			check(y - 1, x + 1);
		}
		//-----------------------------
		if (a[y - 1][x - 1] == 1){
			a[y - 1][x - 1] = 0;
			check(y - 1, x - 1);
		}
		//-----------------------------
		return 0;
	}*/

C++: #include<cstdio>
using namespace std;
void func(int,int);
int a,b;
int sima[51][51];
int cnt;
int main(void)
{
	int i,j,x,y;
	scanf("%d",&a);
	scanf("%d",&b);
	while(!(b==0 && a==0)){
		
		for(i=0;i<b;i++){
			for(j=0;j<a;j++){
				scanf("%d",&sima[i][j]);
			}
		}
		cnt=0;
		for(i=0;i<b;i++){
			for(j=0;j<a;j++){
				if(sima[i][j]==1){
					func(i,j);
					cnt++;
				}
			}
		}
		printf("%d\n",cnt);
		scanf("%d",&a);
		scanf("%d",&b);
	}
	return 0;
}
void func(int y,int x)
{
	if(y-1>=0){
		if(sima[y-1][x]==1){
			sima[y-1][x]=0;
			func(y-1,x);
		}
	}
	if(x-1>=0){
		if(sima[y][x-1]==1){
			sima[y][x-1]=0;
			func(y,x-1);	
		}
	}
	if(y+1<=a){
		if(sima[y+1][x]==1){
			sima[y+1][x]=0;
			func(y+1,x);
		}
	}
	if(x+1<=b){
		if(sima[y][x+1]==1){
			sima[y][x+1]=0;
			func(y,x+1);
		}
	}
	if(y-1>=0 && x+1<=b){
		if(sima[y-1][x+1]==1){
			sima[y-1][x+1]=0;
			func(y-1,x+1);
		}
	}
	if(y-1>=0 && x-1>=0){
		if(sima[y-1][x-1]==1){
			sima[y-1][x-1]=0;
			func(y-1,x-1);
		}
	}
	if(y+1<=a && x+1<=b){
		if(sima[y+1][x+1]==1){
			sima[y+1][x+1]=0;
			func(y+1,x+1);
		}
	}
	if(y+1<=a && x-1>=0){
		if(sima[y+1][x-1]==1){
			sima[y+1][x-1]=0;
			func(y+1,x-1);
		}
	}
}

C++: #include <iostream>
#include <vector>
using namespace std;
#define repeat(i,n) for (int i = 0; (i) <(int) (n); ++(i))
#define repeat_from(i,m,n) for (int i = (m); (i) <(int) (n); ++(i))
void dfs(int x, int y, int n, vector<vector<int> > & k, vector<vector<bool> > const & c) {
    int h = c.size();
    int w = c.front().size();
    if (x < 0 or w <= x or y < 0 or h <= y) return;
    if (k[y][x] or not c[y][x]) return;
    k[y][x] = n;
    repeat_from (dy,-1,1+1) {
        repeat_from (dx,-1,1+1) {
            dfs(x+dx,y+dy,n,k,c);
        }
    }
}
int solve(vector<vector<bool> > const & c) {
    int h = c.size();
    int w = c.front().size();
    vector<vector<int> > k(h, vector<int>(w, 0));
    int n = 0;
    repeat (y,h) {
        repeat (x,w) {
            if (not k[y][x] and c[y][x]) {
                dfs(x,y,++n,k,c);
            }
        }
    }
    return n;
}
int main(void) {
    while (true) {
        int w, h; cin >> w >> h;
        if (w == 0 and h == 0) break;
        vector<vector<bool> > c(h, vector<bool>(w));
        repeat (y,h) {
            repeat (x,w) {
                int t; cin >> t;
                c[y][x] = t;
            }
        }
        cout << solve(c) << endl;
    }
    return 0;
}