c++ - Inheitance not working while workig with pointer

Question

although we are printing bval, output is showing value of dval as well. Whats actual logic does compiler using? My expected output was 00000 00000, but I m getting output as 00000 01010.

#include <iostream>
using namespace std;

class base {
 public:
   int bval;
   base() { bval = 0; }
};

class deri : public base {
  public:
    int dval;
    deri() { dval = 1; }
 };

 void SomeFunc(base *arr , int size) {
   for(int i = 0; i < size; i++, arr++)
     cout << arr-> bval;
   cout<<endl;
 }

 int main() {
   base BaseArr[5];
   SomeFunc(BaseArr, 5);
   deri DeriArr[5];
   SomeFunc(DeriArr, 5);
   return 0;
 }

Answer 1

你在欺骗系统，并得到“切片”。

由于deri大于base，当你这样做时arr++，指针只会base向前推进一个对象。

解决方案是有一个指针数组，并传递 a base **arr，如下所示：

base *foo[5];
base BaseArr[5];
SomeFunc(BaseArr,5);
for(int i = 0; i < 5; i++)
{ 
   foo[i] = &BaseArr[i];
}
SomeFunc(foo, 5);