Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include <iostream>
using namespace std;
int totalRow, totalColumn;


void dfs(int input[50][50], bool visitedIsland[50][50],int row, int col)
{
    //cout << row << " " << col << endl ;
    visitedIsland[row][col] = true;
    if (row < totalRow   && col < totalColumn )
    {
        //Up
        if (row > 0 && input[row - 1][col] == 1 && visitedIsland[row - 1][col] == false)
            dfs(input,visitedIsland,row - 1,col);
        //cout << "up " << row << " " << col << input[row - 1][col] << " " << visitedIsland[row - 1][col] << endl;
        //Down
        if ((row + 1 <= totalRow - 1) && input[row + 1][col] == 1 && visitedIsland[row + 1][col]== false)
            dfs(input,visitedIsland,row + 1,col);
        //cout << "down " << input[1][col] << " " <<visitedIsland[row + 1][col] << endl;
        //Left
        if (col > 0 && input[row][col-1] == 1 && visitedIsland[row][col-1]== false)
            dfs(input,visitedIsland,row,col - 1);
        //cout << "left" << endl;
        //Right
        if ((col + 1 <= totalColumn - 1)&&input[row][col + 1] == 1 && visitedIsland[row][col+1]== false)
            dfs(input,visitedIsland,row,col + 1);
        //Left bottom diagonal
        if (row > 0 && col > 0 && input[row - 1][col - 1] == 1 && visitedIsland[row - 1][col - 1]== false)
            dfs(input,visitedIsland,row - 1,col - 1);
        //cout << "Left bottom " << row << " " << col << input[row - 1][col-1] << " " << visitedIsland[row - 1][col-1] << endl;
        //Left top diagonal
        if ((row + 1 <= totalRow - 1) && col > 0 && input[row + 1][col - 1] == 1 && visitedIsland[row + 1][col - 1]== false)
            dfs(input,visitedIsland,row + 1,col - 1);
        //Right top diagonal
        if ((col + 1 <= totalColumn - 1)&&row > 0 && input[row - 1][col + 1] == 1 && visitedIsland[row - 1][col + 1]== false)
            dfs(input,visitedIsland,row - 1,col +1);
        //cout << "Right top " << row << " " << col << input[row - 1][col+1] << " " << visitedIsland[row - 1][col+1] << endl;
        //Right bottom diagonal
        if ((row + 1 <= totalRow - 1)&&(col + 1 <= totalColumn - 1)&& input[row + 1][col + 1] == 1 && visitedIsland[row + 1][col + 1]== false)
            dfs(input,visitedIsland,row + 1,col +1);
    }
    
}

int main(int argc, const char * argv[]) {
    int row, col;
    while (cin >> col >> row)
    {
        totalRow = row;
        totalColumn = col;
        int numofIsland = 0;
        int input[50][50] = {0};
        bool visitedIsland[50][50] = {false};
        for (int i= 0; i < row; i++)
            for (int j = 0; j < col; j++)
                cin >> input[i][j];
        //checking
        //cout << input[1][0] << " " << input[0][0]<< endl;
        for (int i = 0; i < row; i++)
        {
            for (int j = 0; j < col; j++)
            {
                if (input[i][j] == 1 && !visitedIsland[i][j])
                {
                    //push neighbour
                    numofIsland++;
                    //processed = true;
                    //cout << i << " " << j << endl ;
                    dfs(input,visitedIsland,i,j);
                }
            }
        }
        if (row > 0 &&  col > 0)
            cout << numofIsland << endl;
    }
    return 0;
}

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

using namespace std;

int w, h;
int field[51][51];
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};

void dfs(int x, int y)
{
    field[y][x] = -1;

    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;

        if (field[ny][nx] == 1)
            dfs(nx, ny);
    }
}

int main()
{
    while (cin >> w >> h, w || h)
    {
        for (int y = 0; y < h; y++)
        {
            for (int x = 0; x < w; x++)
            {
                cin >> field[y][x];
            }
        }

        int ans = 0;

        for (int y = 0; y < h; y++)
        {
            for (int x = 0; x < w; x++)
            {
                if (field[y][x] == 1)
                {
                    dfs(x, y);
                    ans++;
                }
            }
        }

        cout << ans << endl;
    }

    return 0;
}