非虚函数声明以= 0结尾

Question

string foo() const = 0;

这个函数声明究竟是什么意思？特别是什么是＆＃39; = 0＆＃39;好的，因为函数未被声明为虚拟？

Answer 1

= 0是该函数是纯虚函数的语法。据我所知，声明还需要在关键字virtual之前。

更多关于此的内容：What does it mean to set the declaration of a function equal to 0? How can you assign an integer to a function?

Difference between a virtual function and a pure virtual function