修复简单typo

[ericzeng95]

sizeof 章节 关于具有虚函数的类的继承的示范代码有误.

CPlusPlusThings/basic_content/sizeof/geninhe.cpp

Lines 49 to 52 in c9d0f14

	class A1 {
	virtual void fun() {}
	};
	class C1 : public A {};

CPlusPlusThings/basic_content/sizeof/geninhe.cpp

Lines 15 to 19 in c9d0f14

	class A {
	public:
	char a;
	int b;
	};

此处的 A 不是具有虚函数的类，C1 正确是示范应是继承 A1

[FlyDragonMan]

I have already received the letter you sent me. I will reply and deal with it as soon as possible.ChenMingMing