c**********e
发帖数: 2007 | 1 Error information in the following code is Error: equals is not a member of
B.
My question: Why equals() is not a member of B but print() is?
While this seems obvious, what is the general rule that a function will be
inherited?
#include
using namespace std;
class A {
public:
bool equal(A a) { return true; }
void print() { cout << "print\n"; }
};
class B: public A {};
int main() {
B b;
bool x = b.equals(b);
b.print();
return 0;
} |
b*****c
发帖数: 1103 | 2 。。。。。
因为equal(A)而不是equal(B)，而且b是B啊 |
S**I
发帖数: 15689 | 3 because "equal" is inherited, but "equals" is not.
of
【在 c**********e 的大作中提到】
: Error information in the following code is Error: equals is not a member of
: B.
: My question: Why equals() is not a member of B but print() is?
: While this seems obvious, what is the general rule that a function will be
: inherited?
: #include
: using namespace std;
: class A {
: public:
: bool equal(A a) { return true; }
|
b*****c
发帖数: 1103 | 4 哦哦哦，另外一个问题，B不需要显式转换A吗？？
【在 S**I 的大作中提到】
: because "equal" is inherited, but "equals" is not.
:
: of
|
r*******y
发帖数: 1081 | 5 you defined equal instead of equals
of
【在 c**********e 的大作中提到】
: Error information in the following code is Error: equals is not a member of
: B.
: My question: Why equals() is not a member of B but print() is?
: While this seems obvious, what is the general rule that a function will be
: inherited?
: #include
: using namespace std;
: class A {
: public:
: bool equal(A a) { return true; }
|
r*******y
发帖数: 1081 | 6 B will slice down to A
【在 b*****c 的大作中提到】
: 哦哦哦，另外一个问题，B不需要显式转换A吗？？
|
c**********e
发帖数: 2007 | 7 Faint. I made such a low level mistake. Then what is the output of the
following code?
#include
using namespace std;
class A {
public:
bool equals(A a) { return data==a.data; }
void setData(int input) { data=input; }
private:
int data;
};
class B: public A {};
void main() {
A a;
a.setData(7);
B b;
b.setData(7);
cout << a.equals(b) << endl;
cout << b.equals(a) << endl;
} |
t*****n
发帖数: 25 | 8 1
1
【在 c**********e 的大作中提到】
: Faint. I made such a low level mistake. Then what is the output of the
: following code?
: #include
: using namespace std;
: class A {
: public:
: bool equals(A a) { return data==a.data; }
: void setData(int input) { data=input; }
: private:
: int data;
|
b*****c
发帖数: 1103 | |
f********n
发帖数: 1163 | 10 确认一下：
cout << a.equals(b) << endl;
比较的是a的data和b.data？ |
j********x
发帖数: 2330 | 11 这还需要确认么
【在 f********n 的大作中提到】
: 确认一下：
: cout << a.equals(b) << endl;
: 比较的是a的data和b.data？
|
