C :

#include<stdio.h>
#include<string.h>
int n,m;
char s[104][104];
int dir[8][2]={-1,-1,-1,0,-1,1,0,-1,0,1,1,-1,1,0,1,1};
int vis[104][104];
void dfs(int x,int y)
{
    int i;
    if(x<0||x>=n||y<0||y>=m||vis[x][y]||s[x][y]=='*') return;
    vis[x][y]=1;
    for(i=0; i<8; i++)
        dfs(x+dir[i][0],y+dir[i][1]);
}
int main()
{
    int i,j,ans,t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        memset(s,0,sizeof(s));
        memset(vis,0,sizeof(vis));
        ans=0;
        for(i=0;i<n;i++)
            scanf("%s",s[i]);
        for(i=0;i<n;i++)
            for(j=0;j<m;j++)
                if(s[i][j]=='@'&&!vis[i][j])
                {
                    ans++;
                    dfs(i,j);
                }
        printf("%d\n",ans);
    }
    return 0;
}

C++ :

#include <iostream>
#include <cstring>
#include <fstream>

using namespace std;

char mat[115][115];
int visited[115][115];

void dfs(int x,int y)
{
    if((visited[x][y]==1 || mat[x][y]=='*' ))
        return;
    visited[x][y]=1;
    dfs(x-1,y-1);
    dfs(x-1,y);
    dfs(x-1,y+1);

    dfs(x,y-1);
    dfs(x,y+1);

    dfs(x+1,y-1);
    dfs(x+1,y);
    dfs(x+1,y+1);
}

int main()
{
	//ifstream cin;
	//cin.open("5.in");
	//ofstream cout;
	//cout.open("5.out");
	int length,height;
	int testcase;
	cin>>testcase;
	while(testcase--)
    {
    	cin>>length>>height;

        memset(mat,'*',sizeof(mat));
        memset(visited,0,sizeof(visited));
        int count=0;
        for(int i=1;i<=length;i++)
        {
            for(int j=1;j<=height;j++)
            {
                cin>>mat[i][j];
            }
        }

        for(int i=1;i<=length;i++)
        {
            for(int j=1;j<=height;j++)
            {
                if(mat[i][j]=='@' && visited[i][j]==0)
                {
                    dfs(i,j);
                    count++;
                }
            }
        }
        cout<<count<<endl;
    }
    return 0;
}