摘要:
No.If an exception occurs during the Fred constructor of p = new Fred(), the C++ language guarantees that the memory sizeof(Fred) bytes that were allo... 阅读全文
摘要:
Because converting Foo** → const Foo** would be invalid and dangerous.C++ allows the (safe) conversion Foo* → Foo const*, but gives an error if you tr... 阅读全文
摘要:
权限管理有两个层面第一层区分用户:文件属主(u), 组用户(g), 其它(o)第二层区分权限:读(r),写(w),可执行(x)这两个层次构成文件权限管理的二维结构 u g orwx实际中我们用9个bit位来分别表示这张表里九个位置的值在八进制下就是三位数了所以最常见到的chmod 777 filen... 阅读全文