/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:8:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   if(a[i]=0)
            ^
/in/foo.cc:17:4: error: expected ';' before '}' token
    }
    ^
/in/foo.cc:21:1: error: a function-definition is not allowed here before '{' token
 {
 ^