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 <functional>
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    while (true) {
        int w, h;
        cin >> w >> h;
        if (w == 0 && h == 0) {
            return 0;
        }
        vector<vector<int>> v(h, vector<int>(w, -1));
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                cin >> v[i][j];
            }
        }
        constexpr int MIN_ID = 10;
        function<int(int, int, int)> f = [&v, &f, w, h, MIN_ID](int i, int j,
                                                                int id) {
            // ?????¢????¶???????
            if (i == -1 || j == -1 || i == h || j == w) {
                return 0;
            }
            // ?????§?????¶????±?????????????
            else if (MIN_ID <= v[i][j] && v[i][j] <= id) {
                return 0;
            }
            // ???
            else if (v[i][j] == 0) {
                return 0;
            }
            else {
                v[i][j] = id;
                int r = 1;
                r += f(i - 1, j - 1, id);
                r += f(i - 1, j, id);
                r += f(i - 1, j + 1, id);
                r += f(i, j - 1, id);
                r += f(i, j + 1, id);
                r += f(i + 1, j - 1, id);
                r += f(i + 1, j, id);
                r += f(i + 1, j + 1, id);
                return r;
            }
        };
        int islandId = MIN_ID;
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                auto r = f(i, j, islandId);
                if (r > 0) {
                    islandId += 1;
                }
            }
        }

        cout << (islandId - MIN_ID) << endl;
    }
}

C++: #include <iostream>

using namespace std;

int m[51][51];
int w, h;
int isl;
const int dx[] = {0, 1, 1, 1, 0, -1, -1, -1};
const int dy[] = {-1, -1, 0, 1, 1, 1, 0, -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 >= w || ny >= h)
            continue;
        else if (m[nx][ny] == 1)
            dfs(nx, ny);
    }
}

int main()
{
    while (cin >> w >> h, w || h) {
        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) {
                    isl++;
                    dfs(i, j);
                }
            
        cout << isl << endl;
    }

    return 0;
}

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

int myMap[50][50];
int w, h;
int ans;

bool safe(int x, int y){
    return (0 <= x && 0 <= y) && (x < w && y < h);
}

void del(int x, int y){
    myMap[x][y] = 0;
    if (safe(x+1, y) && myMap[x+1][y]) del(x+1, y);
    if (safe(x+1, y+1) && myMap[x+1][y+1]) del(x+1, y+1);
    if (safe(x+1, y-1) && myMap[x+1][y-1]) del(x+1, y-1);
    if (safe(x, y+1) && myMap[x][y+1]) del(x, y+1);
    if (safe(x, y-1) && myMap[x][y-1]) del(x, y-1);
    if (safe(x-1, y-1) && myMap[x-1][y-1]) del(x-1, y-1);
    if (safe(x-1, y+1) && myMap[x-1][y+1]) del(x-1, y+1);
    if (safe(x-1, y) && myMap[x-1][y]) del(x-1, y);
    return;
}

int main(){

    while (1){
	cin >> w >> h;
	if (w == 0 && h == 0) break;

	for (int i = 0; i < h; i++){
	    for (int j = 0; j < w; j++){
		cin >> myMap[i][j];
	    }
	}

	ans = 0;	
	for (int i = 0; i < w; i++){
	    for (int j = 0; j < h; j++){
		if (myMap[i][j] == 1){
		    ans++;
		    del(i, j);
		}
	    }
	}

	cout << ans << endl;
    }
    
}

C++: #define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <fstream>
#include <set>
#include <utility>
#include <algorithm>
#include <queue>
#include <stack>
#include <deque>
#include <numeric>
#include <sstream>
#include <list>
#include <map>
#include <functional>
#include <iterator>

#define rep(i,p,n) for(int i=(int)p;i<(int)n;i++)
#define repp(i,p,n) for(int i=(int)p;i>=(int)n;i--)
#define Sort(x) sort(x.begin(),x.end())
#define PSort(x) sort(begin(x), end(x), pairCompare)
#define ll long long
#define INF 2000000000
#define pb push_back
#define mp make_pair
#define PI 3.14159265358979
int dx[4] = { -1,0,1,0 }, dy[4] = { 0,1,0,-1 };
using namespace std;

vector<vector<int>> v;
int w, h;

void dfs(int y, int x) {
	if (v[y][x] == 1)v[y][x] = 0;

	for (int i = -1; i <= 1; i++) {
		for (int j = -1; j <= 1; j++) {
			int nx = x + i, ny = y + j;

			if (!(nx < 0 || ny < 0 || nx >= w||ny >= h)&&v[ny][nx] == 1) dfs(ny, nx);
		}
	}
	
	return;
}

int main(){
	while (1) {
		int ans=0;
		cin >> w >> h;
		if (w == 0 && h == 0)break;
		v.resize(h, vector<int>(w));
		rep(i, 0, h) {
			rep(j, 0, w) {
				cin >> v[i][j];
			}
		}

		rep(i, 0, h) {
			rep(j, 0, w) {
				if (v[i][j] == 1) {
					ans++;
					dfs(i, j);
				}
			}
		}
		cout << ans << endl;
	}
	
	return 0;
}

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