Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 1000005), 1000005)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func getNextInt64(scanner *bufio.Scanner) int64 {
	i, _ := strconv.ParseInt(getNextString(scanner), 10, 64)
	return i
}

func getNextUint64(scanner *bufio.Scanner) uint64 {
	i, _ := strconv.ParseUint(getNextString(scanner), 10, 64)
	return i
}

func getNextFloat64(scanner *bufio.Scanner) float64 {
	i, _ := strconv.ParseFloat(getNextString(scanner), 64)
	return i
}

func main() {
	fp := os.Stdin
	wfp := os.Stdout
	cnt := 0

	if os.Getenv("MASPY") == "ますピ" {
		fp, _ = os.Open(os.Getenv("BEET_THE_HARMONY_OF_PERFECT"))
		cnt = 0
	}
	if os.Getenv("MASPYPY") == "ますピッピ" {
		wfp, _ = os.Create(os.Getenv("NGTKANA_IS_GENIUS10"))
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(wfp)
	for solve(scanner, writer) {

	}
	for i := 0; i < cnt; i++ {
		fmt.Fprintln(writer, "-----------------------------------")
		solve(scanner, writer)
	}
	writer.Flush()
}

func solve(scanner *bufio.Scanner, writer *bufio.Writer) bool {
	sol := solver{}
	sol.w = getNextInt(scanner)
	sol.h = getNextInt(scanner)
	if sol.w == 0 && sol.h == 0 {
		return false
	}
	sol.land = makeInts(sol.h, sol.w)
	for y := 0; y < sol.h; y++ {
		for x := 0; x < sol.w; x++ {
			sol.land[y][x] = getNextInt(scanner)
		}
	}
	ans := 0
	for y := 0; y < sol.h; y++ {
		for x := 0; x < sol.w; x++ {
			if sol.land[y][x] == 0 {
				continue
			}
			ans++
			sol.dfs(y, x)
		}
	}
	fmt.Fprintln(writer, ans)
	return true
}

type solver struct {
	w, h int
	land [][]int
}

func (sol *solver) dfs(y, x int) {
	if y < 0 {
		return
	}
	if y >= sol.h {
		return
	}
	if x < 0 {
		return
	}
	if x >= sol.w {
		return
	}
	if sol.land[y][x] == 0 {
		return
	}
	sol.land[y][x] = 0
	dy := [8]int{-1, -1, -1, 0, 0, 1, 1, 1}
	dx := [8]int{-1, 0, 1, -1, 1, -1, 0, 1}
	for i := 0; i < 8; i++ {
		sol.dfs(y+dy[i], x+dx[i])
	}
}
func makeInts(h, w int) [][]int {
	index := make([][]int, h, h)
	data := make([]int, h*w, h*w)
	for i := 0; i < h; i++ {
		index[i] = data[i*w : (i+1)*w]
	}
	return index
}

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

using namespace std;

int w,h,res;
vector<vector<int> > map;
vector<vector<bool> > visited;
int dx[8] = {0,1,0,-1,1,1,-1,-1};
int dy[8] = {1,0,-1,0,1,-1,1,-1};

void bfs(int y,int x){
	if(y >= h || y < 0 || x >= w || x < 0)return;
	if(map[y][x] == 0)return;
	if(visited[y][x])return;
	visited[y][x] = true;
	for(int i=0;i<8;++i){
		bfs(y+dy[i],x+dx[i]);
	}
}

int main(void){
	while(1){
		res = 0;
		cin >> w >> h;
		if(w == 0 && h == 0)break;
		map.resize(h);
		visited.resize(h);
		for(int i=0;i<h;++i){
			map[i].resize(w);
			visited[i].resize(w);
			for(int j=0;j<w;++j){
				visited[i][j] = false;
				cin >> map[i][j];
			}
		}
		for(int i=0;i<h;++i){
			for(int j=0;j<w;++j){
				if(map[i][j] == 1&& visited[i][j] == false){
					bfs(i,j);
					res++;
				}
			}
		}
		cout << res << endl;
	}
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
using namespace std;

struct UnionFind {
        int n;
        vector<int> parent;
        vector<int> rank;
        vector<int> num;
        int find(int x) {
                if (parent[x] == x) return  x;
                return parent[x] = find(parent[x]);
        }
        UnionFind(int n_) {
                n = n_;
                parent.resize(n);
                for (int i = 0; i < n; i ++) parent[i] = i;
                rank.assign(n, 0);
                num.assign(n, 1);
        }
        void unite(int x, int y) {
                if ((x = find(x)) != (y = find(y))) {
                        if (rank[x] < rank[y]) {
                                parent[x] = y;
                                num[y] += num[x];
                        } else {
                                parent[y] = x;
                                if (rank[x] == rank[y]) rank[x] ++;
                                num[x] += num[y];
                        }
                        n --;
                }
        }
        bool same(int x, int y) { return find(x) == find(y); }
        int get() { return n; }
        int get(int x) { return num[find(x)]; }
};

int main() {
        int w, h;
        while (scanf("%d%d", &w, &h), w) {
                vector<vector<int>> s(h, vector<int> (w));
                int lands = 0;
                map<pair<int, int>, int> ptol;
                for (int i = 0; i < h; i ++) {
                        for (int j = 0; j < w; j ++){
                                scanf("%d", &s[i][j]);
                                if (s[i][j] == 1) {
                                        ptol[make_pair(i, j)] = lands;
                                        lands ++;
                                }
                        }
                }
                UnionFind uf(lands);
                //cerr << lands << endl;
                for (int i = 0; i < h - 1; i ++) {
                        for (int j = 0; j < w - 1; j ++) {
                                if (s[i][j] == 1) {
                                        if (s[i + 1][j] == 1) uf.unite(ptol[make_pair(i, j)], ptol[make_pair(i + 1, j)]);
                                        if (s[i + 1][j + 1] == 1) uf.unite(ptol[make_pair(i, j)], ptol[make_pair(i + 1, j + 1)]);
                                        if (s[i][j + 1] == 1) uf.unite(ptol[make_pair(i, j)], ptol[make_pair(i, j + 1)]);
                                }
                        }
                }
                for (int i = 0; i < h - 1; i ++) {
                        if (s[i][w - 1] == 1 && s[i + 1][w - 1] == 1) uf.unite(ptol[make_pair(i, w - 1)], ptol[make_pair(i + 1, w - 1)]);
                        if (w > 1 && s[i][w - 1] == 1 && s[i + 1][w - 2] == 1) uf.unite(ptol[make_pair(i, w - 1)], ptol[make_pair(i + 1, w - 2)]);
                }
                for (int j = 0; j < w - 1; j ++) {
                        if (s[h - 1][j] == 1 && s[h - 1][j + 1] == 1) uf.unite(ptol[make_pair(h - 1, j)], ptol[make_pair(h - 1, j + 1)]);
                        if (h > 1 && s[h - 1][j] == 1 && s[h - 2][j + 1] == 1) uf.unite(ptol[make_pair(h - 1, j)], ptol[make_pair(h - 2, j + 1)]);
                }
                printf("%d\n", uf.get());
        }
        return 0;
}