I'm trying to do the following:
class Book {
std::string m_title;
std::string m_author;
int m_noPages;
public:
Book(const std::istream& is) {
std::string bookString;
is >> bookString;
// ...
}
};
... After this, I will proceed to separate the is input into m_title, m_author, and m_noPages, but why won't the two lines above inside the constructor work?
When reading from (and writing to) a stream, the stream is modified to track what was read (or written). This makes a const, thus not modifiable, stream next to useless, and it can't be used by >>. Remove the const.
class Book {
std::string m_title;
std::string m_author;
int m_noPages;
public:
Book(const std::istream& is) {
// ^^^^^
// kill meeeeee!
std::string bookString;
is >> bookString;
// ...
}
};
Language-wise, the prototype for operator >> should look something like
std::istream& operator>>(std::istream& is, T& obj)
(example prototype looted from What are the basic rules and idioms for operator overloading?).
It will accept std::istream &, but not a const std::istream &.
