c++:报错Undefined symbols for architecture x86_64:

在学习c++是报了这个错：

Undefined symbols for architecture x86_64:
  "StackMy, std::__1::allocator > >::~StackMy()", referenced from:
      _main in main.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

最后查证是因为头文件中自定义了析构函数，但没有实现这个析构函数导致的报错，在此记录一下