当你的在xcode出现以下错误时,
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_ammo", referenced from: (这里就是ammo文件错误)
objc-class-ref in main.o
"_OBJC_CLASS_$_gun", referenced from: (这里就是gun文件错误)
objc-class-ref in main.o
"_OBJC_IVAR_$_ammo._ammonumber", referenced from: (这里就是提示你的ammo文件中的.m错误)
_main in main.o
"_OBJC_IVAR_$_gun._size", referenced from: (这里就是gun文件中的.m错误)
_main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
修改方式:错误原因可能是你的target选择错误,你需要找到每个.m文件,然后勾选你要调试的目标。如图