禁用复制构造函数
我有一堂课: class SymbolIndexer { protected: SymbolIndexer ( ) { } public: static inline SymbolIndexer & GetUniqueInstance ( ) { static SymbolIndexer uniqueinstance_ ; return uniqueinstance_ ; } }; 我应该如何修改它以禁用如下代码: SymbolIndexer symbol_indexer_ = SymbolIndexer::GetUniqueInstance ( ); 并且只允许像这样的代码: SymbolIndexer & ref_symbol_indexer_ = SymbolIndexer::GetUniqueInstance ( );