使用qt Creator IDE找不到架构x86_64（C++）的符号[重复]

Question

我基本上被我想测试的程序之一卡住了，因为我一直收到这个符号未找到错误。

我的程序很简单，在 C++ 方面我是一个极端的初学者，所以我只是想学习一些继承的东西。下面是程序的结构：

The object diagram of the program

所以这很简单，我有 2 个抽象类，即 Vehicle.h 和 MotorVehicle.h , Bus 和 Car 将继承 MotorVehicle.h 的属性 和 Bicycle 将是 Vehicle.h 的后代，因为它不是机动车。

代码和文件非常多，所以如果有人想知道代码，我就把qt项目文件夹留在这里：

https://drive.google.com/open?id=0B1hy9BsfLLwab19wODR2UWhnRmc

现在，由于某种原因，每当我想运行程序时，我都会收到 Symbol(s) not found for architecture x86_64 错误，我检查了 编译输出的 qt Creator，它是这样说的：

Undefined symbols for architecture x86_64:
  "vehicle::MotorVehicle::~MotorVehicle()", referenced from:
  Car::~Car() in main.o
  Bus::~Bus() in main.o
  Car::~Car() in Car.o
  Bus::~Bus() in Bus.o
  "vehicle::Vehicle::~Vehicle()", referenced from:
  Bicycle::~Bicycle() in main.o
  Bicycle::~Bicycle() in Bicycle.o
  "typeinfo for vehicle::MotorVehicle", referenced from:
  typeinfo for Car in Car.o
  typeinfo for Bus in Bus.o
  "typeinfo for vehicle::Vehicle", referenced from:
  typeinfo for Bicycle in Bicycle.o
  "vtable for vehicle::MotorVehicle", referenced from:
  vehicle::MotorVehicle::MotorVehicle(int, int, int, double) in main.o
  vehicle::MotorVehicle::MotorVehicle(int, int, int,    std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, double) in main.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for vehicle::Vehicle", referenced from:
  vehicle::Vehicle::Vehicle(int, int, is std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) in main.o
  NOTE: a missing vtable usually means the first non-inline virtual member    function has no definition.
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Vehicles] Error 1
02:38:06: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project Vehicles (kit: Desktop Qt 5.8.0 clang 64bit)
When executing step "Make"

我只想说我很困惑，因为我对 C++ 很陌生，我已经尝试从其他 SO 讨论线程中寻找答案，但我只是找不到与我相关的任何内容，所以看起来（或也许我只是还不够努力）

大家好，提前多谢

Answer 1

您将您的析构函数声明到 Vehicle 类中，virtual ~Vehicle() 但您没有为它提供实现。如果你不想释放任何东西，你应该像这样声明它virtual ~Vehicle() {}。 MotorVehicle 析构函数也是如此。

“未找到符号”错误非常具有误导性。其实就是说有一个定义好的符号，主要是函数，没有找到它的实现。