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 <iostream>
using namespace std;

constexpr int MAX_H = 55;
constexpr int MAX_W = 55;

int H, W;
int grid[MAX_H][MAX_W];
bool reached[MAX_H][MAX_W];

#define OCTAS
#ifdef OCTAS
constexpr int dh[]{-1, -1, -1, 0, 0, +1, +1, +1};
constexpr int dw[]{-1, 0, +1, -1, +1, -1, 0, +1};
#else
constexpr int dh[]{-1, 0, 0, +1};
constexpr int dw[]{0, -1, +1, 0};
#endif

void dfs(int h, int w) {
  reached[h][w] = true;

  for (int i{}; i < sizeof(dh) / sizeof(int); ++i) {
    int nh = h + dh[i];
    if (nh < 0 || nh >= H)
      continue;
    int nw = w + dw[i];
    if (nw < 0 || nw >= W)
      continue;
    if (grid[nh][nw] == 0 || reached[nh][nw])
      continue;
    dfs(nh, nw);
  }
}

int main() {
  while (true) {
    cin >> H >> W;
    if (H == 0 && W == 0)
      break;
    for (int h{}; h < H; ++h) {
      for (int w{}; w < W; ++w) {
        reached[h][w] = false;
        cin >> grid[h][w];
      }
    }

    int island{};
    for (int h{}; h < H; ++h) {
      for (int w{}; w < W; ++w) {
        if (grid[h][w] == 0 || reached[h][w])
          continue;
        dfs(h, w);
        ++island;
      }
    }

    cout << island << endl;
  }

  return 0;
}

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

constexpr int MAX_H = 50;
constexpr int MAX_W = 50;

int H, W;
char grid[MAX_H][MAX_W];
bool reached[MAX_H][MAX_W];

#define OCTAS
#ifdef OCTAS
constexpr int dh[]{-1, -1, -1, 0, 0, +1, +1, +1};
constexpr int dw[]{-1, 0, +1, -1, +1, -1, 0, +1};
#else
constexpr int dh[]{-1, 0, 0, +1};
constexpr int dw[]{0, -1, +1, 0};
#endif

void dfs(int h, int w) {
  reached[h][w] = true;

  for (int i{}; i < sizeof(dh) / sizeof(int); ++i) {
    int nh = h + dh[i];
    if (nh < 0 || nh >= H)
      continue;
    int nw = w + dw[i];
    if (nw < 0 || nw >= W)
      continue;
    if (grid[nh][nw] == '0' || reached[nh][nw])
      continue;
    dfs(nh, nw);
  }
}

int main() {
  while (true) {
    cin >> H >> W;
    if (H == 0 && W == 0)
      break;
    fill(reached[0], reached[0] + MAX_H * MAX_W, false);
    for (int h{}; h < H; ++h) {
      for (int w{}; w < W; ++w) {
        cin >> grid[h][w];
      }
    }

    int island{};
    for (int h{}; h < H; ++h) {
      for (int w{}; w < W; ++w) {
        if (grid[h][w] == '0' || reached[h][w])
          continue;
        dfs(h, w);
        ++island;
      }
    }

    cout << island << endl;
  }

  return 0;
}

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

struct mapst {
	int x, y;
};

#define func(x,y) (c[y][x]&&!f[y][x])

int main() {
	int w, h, ans=0;
	int c[52][52]={{0}}, f[52][52]={{1}};
	int dx[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
	int dy[8] = {0, -1, -1, -1, 0, 1, 1, 1};
	queue<mapst> q;
	while(1) {
		cin >> w >> h;
		if(!w&&!h) break;
		ans = 0;
		for(int i=1; i<=h; ++i) for(int j=1; j<=w; ++j) {
			cin >> c[i][j];
			f[i][j] = 0;
		}
		for(int i=1; i<=h; ++i) for(int j=1; j<=w; ++j) {
			if(func(j,i)) {
				mapst m = {j, i}, ms;
				q.push(m);
				ans++;
				do {
					m = q.front();
					q.pop();
					f[m.y][m.x] = 1;
					for(int k=0; k<8; k++) {
						if(func(m.x+dx[k],m.y+dy[k])) {
							ms.x = m.x+dx[k]; ms.y = m.y+dy[k];
							q.push(ms);
						}
					}
				}while(!q.empty());
			}
		}
		cout << ans << endl;
	}
}

C++: #include "bits/stdc++.h"
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;

using ll = long long;

int w, h, c[52][52];

void dfs(int i, int j) {
    c[i][j] = 0;
    for (int k = i - 1; k < i + 2; k++) {
        for (int l = j - 1; l < j + 2; l++) {
            if (c[k][l] == 1) dfs(k, l);
        }
    }
}

int main() {
    cin >> w >> h;
    while (w) {
        rep(i, 52) rep(j, 52) c[i][j] = 0;
        rep(i, h) rep(j, w) cin >> c[i + 1][j + 1];
        int ans = 0;
        rep(i, h + 2) rep(j, w + 2) {
            if (c[i][j] == 1) {
                dfs(i, j);
                ans++;
            }
        }
        cout << ans << "\n";
        cin >> w >> h;
    }
}

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

using namespace std;

int W, H;
int C[50][50];

void DFS(int h, int w)
{
    if (w < 0 || w >= W) return;
    if (h < 0 || h >= H) return;
    if (C[h][w] == 0) return;
    C[h][w] = 0;

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

    for (int i = 0; i < 8; ++i) {
        DFS(h+dx[i], w+dy[i]);
    }
}

int main()
{
    while (1) {
        cin >> W >> H;
        if (W == 0 && H == 0) {
            break;
        }

        for (int h = 0; h < H; ++h) {
            for (int w = 0; w < W; ++w) {
                cin >> C[h][w];
            }
        }

        int Res = 0;
        for (int h = 0; h < H; ++h) {
            for (int w = 0; w < W; ++w) {
                if (C[h][w] == 1) {
                    DFS(h, w);
                    ++Res;
                }
            }
        }
        cout << Res << endl;
    }

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;


int main(void){

	int w, h;

	while (cin >> w >> h, w, h){
		int c[100][100] = { 0 };
		vector<bool> island;
		island.push_back(false);

		for (int j = 1; j <= h; j++){
			for (int i = 1; i <= w; i++){
				cin >> c[j][i];
			}
		}

		int count = 1;
		for (int j = 1; j <= h; j++){
			for (int i = 1; i <= w; i++){
				if (c[j][i] != 0){

					if (c[j][i - 1] != 0) c[j][i] = c[j][i - 1];
					else if (c[j - 1][i + 1] != 0) c[j][i] = c[j - 1][i + 1];
					else if (c[j - 1][i] != 0) c[j][i] = c[j - 1][i];
					else if (c[j - 1][i - 1] != 0) c[j][i] = c[j - 1][i - 1];
					else{
						c[j][i] = count;
						count++;
						island.push_back(true);
					}

					bool buff = island[c[j][i]];

					island[c[j][i - 1]] = island[c[j - 1][i + 1]] = island[c[j - 1][i]] = island[c[j - 1][i - 1]] = false;
					island[c[j][i]] = buff && true;

				}
			}
		}

		int result = 0;
		vector<bool>::iterator it;
		for (it = island.begin(); it != island.end(); ++it) 	if (*it == true) result++;
		
		cout << result << endl;

	}

	return 0;
}

/*
for(i=0;i<N;i++){
cin >> X[i];
}


for(i=0;i<N;i++){
for(j=0;j<N;j++){
cin >> X[i][j];
}
}
*/