C++ Cast 运算符重载
C++ Cast operator overload
我有一个 class,只有一个 int 成员,例如:
class NewInt {
int data;
public:
NewInt(int val=0) { //constructor
data = val;
}
int operator int(NewInt toCast) { //This is my faulty definition
return toCast.data;
}
};
因此,当我调用 int()
转换运算符时,我会 return data
例如:
int main() {
NewInt A(10);
cout << int(A);
}
我会打印 10 个。
A user-defined cast or conversion operator 具有以下语法:
operator conversion-type-id
explicit operator conversion-type-id
(C++11 起)
explicit ( expression ) operator conversion-type-id
(C++20 起)
代码 [Compiler Explorer]:
#include <iostream>
class NewInt
{
int data;
public:
NewInt(int val=0)
{
data = val;
}
// Note that conversion-type-id "int" is the implied return type.
// Returns by value so "const" is a better fit in this case.
operator int() const
{
return data;
}
};
int main()
{
NewInt A(10);
std::cout << int(A);
return 0;
}
我有一个 class,只有一个 int 成员,例如:
class NewInt {
int data;
public:
NewInt(int val=0) { //constructor
data = val;
}
int operator int(NewInt toCast) { //This is my faulty definition
return toCast.data;
}
};
因此,当我调用 int()
转换运算符时,我会 return data
例如:
int main() {
NewInt A(10);
cout << int(A);
}
我会打印 10 个。
A user-defined cast or conversion operator 具有以下语法:
operator conversion-type-id
explicit operator conversion-type-id
(C++11 起)explicit ( expression ) operator conversion-type-id
(C++20 起)
代码 [Compiler Explorer]:
#include <iostream>
class NewInt
{
int data;
public:
NewInt(int val=0)
{
data = val;
}
// Note that conversion-type-id "int" is the implied return type.
// Returns by value so "const" is a better fit in this case.
operator int() const
{
return data;
}
};
int main()
{
NewInt A(10);
std::cout << int(A);
return 0;
}