POJ 1979 Red and Black

#include <cstdio>

int w, h;
char s[25][25];
int cnt;

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

void dfs(int x, int y)
{
    if(inRoom(x, y) && s[x][y] == ‘.‘){
        ++cnt;
        s[x][y] = ‘#‘;
        dfs(x-1, y);
        dfs(x+1, y);
        dfs(x, y-1);
        dfs(x, y+1);
    }
}

void solve()
{
    int x, y;
    for(int i = 0; i < h; ++i)
        for(int j = 0; j < w; ++j)
            if(s[i][j] == ‘@‘){
                x = i;
                y = j;
                s[i][j] = ‘.‘;
                goto END;
            }
    END:
    cnt = 0;
    dfs(x, y);
    printf("%d\n", cnt);
}

int main()
{
    while(scanf("%d%d", &w, &h), w){
        for(int i = 0; i < h; ++i)
            scanf("%s", s[i]);
        solve();
    }
    return 0;
}