类 Demo 里声明了一个虚函数,为什么调用虚函数时core 了呢? core 信息: ``` language Program terminated with signal SIGSEGV, Segmentation fault. #0 0x0000aab1a12ab in vtable for __cxxabiv1::__si_class_type_info () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 ``` ``` c++ class Demo { public: virtual int32_t Demo() { return 0; } }; int main() { Demo* d = new Demo(); d->show(); // core 到这里了 return 0; } ```