////////////////// // DutchAuction // ////////////////// DutchAuction::DutchAuction( const string newProductName ) : Auction( newProductName ) { // cout << "max sum\n"; // cin >> currentPrice; } /tmp/cck7buf8.o: In function `DutchAuction::DutchAuction(std::basic_string, std::allocator >)': auction.cpp:(.text+0x4e9): undefined reference to `vtable for DutchAuction' /tmp/cck7buf8.o: In function `DutchAuction::DutchAuction(std::basic_string, std::allocator >)': auction.cpp:(.text+0x551): undefined reference to `vtable for DutchAuction' collect2: ld returned 1 exit status