c++ - Xcode Apple Mach-0 链接器 (Id) 错误

Question

我查看了许多其他类似的问题，但我无法弄清楚这些错误。

“Fighter::takeDamage(int)”，引用自：

  vtable for Fighter in Fighter-D8AE20C4CA0F2F89.o
  vtable for Archer in Archer-2F4D431E1CB47450.o
  vtable for Cleric in Cleric-1332D02E7E206D4D.o

“Fighter::useAbility()”，引用自：

  vtable for Fighter in Fighter-D8AE20C4CA0F2F89.o

“Fighter::reset()”，引用自：

  vtable for Fighter in Fighter-D8AE20C4CA0F2F89.o

“Fighter::getDamage()”，引用自：

  vtable for Fighter in Fighter-D8AE20C4CA0F2F89.o

“Fighter::Fighter(std::__1::basic_string, std::__1::allocator >, int, int, int, int)”，引用自：

  Robot::Robot(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int, int, int) in Robot-D3F84EA62D808B55.o
  Archer::Archer(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int, int, int) in Archer-2F4D431E1CB47450.o
  Cleric::Cleric(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int, int, int) in Cleric-1332D02E7E206D4D.o

ld：未找到架构 x86_64 的符号

clang：错误：链接器命令失败，退出代码为 1（使用 -v 查看调用）