如何通过参数的某些性质而不是其确切类型来指定参数类型? [英]How do I specify a parameter type by some quality of the parameter rather than its exact type?
C++ 如果我知道几个可能的确切类型,我应该使用什么类型? [英]C++ what type should I use if I know the exact type from a few possible?
我怎么知道指向基类对象的指针数组中元素的类型,它将为派生类分配内存 [英]how do i know what is the type of an element in an array of pointers to an object of base class, that will allocate memory for derived classes