答案真的在于声明：

    Base* virtual_derived = new VirtualDerived;

您正试图释放'malloc'未返回的地址。要了解原因，请将此行替换为

You are trying to 'free' an address that was not returned by 'malloc'. To understand why, replace this line with

    VirtualDerived* x = new VirtualDerived;
    Base* virtual_derived = x;

如果您打印这两个地址，您会注意到'x'和'virtual_derived'具有不同的值。 'malloc'返回的地址（通过'new'）是'x'，传递给'free'的地址（通过'delete'）是'virtual_derived'。

If you print these two addresses, you will notice that 'x' and 'virtual_derived' have different values. The address that 'malloc' returned (via 'new') is 'x' and the address that was passed to 'free' (via 'delete') is 'virtual_derived'.