C++ Primer, Edisi Kelima: Dasar Komunikasi C++

Dalam C++, komunikasi adalah aliran, bukan peristiwa penyimpanan statis. Pustaka iostream menggunakan hirarki polimorfik di mana kelas khusus seperti ifstream (file) dan istringstream (memori) mewarisi dari istream. Ini memungkinkan Warisan Stream: fungsi yang dirancang untuk stream dasar dapat memproses data dari sumber apa pun secara transparan.

Kendala Tidak Dapat Disalin

Stream merepresentasikan koneksi unik dan berstatus ke perangkat keras. Untuk mencegah beberapa objek bersaing atas penunjuk file atau buffer konsol yang sama, objek IO tidak dapat disalin atau ditugaskan. Mencoba kode seperti ofstream out1, out2; out1 = out2; akan menghasilkan kesalahan kompilator. Akibatnya, objek IO harus dilewatkan melalui referensi non-konstan.

Jembatan Berurutan

Sementara stream menyediakan antarmuka, kontainer berurutan (vector, list) menyediakan memori. Data yang masuk melalui stream biasanya diatur dalam kontainer ini, memilih vector untuk kecepatan atau list untuk penyisipan yang fleksibel.

TERMINALbash — 80x24

> Ready. Click "Run" to execute.

QUESTION 1

What causes the termination of while (cin >> i)?

The stream reaching a value of 0.

Encountering end-of-file (EOF) or an invalid input type.

The buffer becoming full.

A semicolon in the input stream.

QUESTION 2

Identify the error: ofstream out1, out2; out1 = out2;

Logic error: Files cannot have the same name.

Syntax error: Stream assignment is prohibited.

Runtime error: Buffer overflow.

No error; this is standard C++ usage.

QUESTION 3

How should an istream be passed to a function that reads from it?

By value (e.g., void func(istream is))

By const reference (e.g., void func(const istream &is))

By non-const reference (e.g., void func(istream &is))

As a pointer to a const object.

QUESTION 4

What is the primary flaw in this loop? while (iter1 < iter2) where iter is a list<int>::iterator?

Lists only support != comparison for iterators.

The loop will result in an infinite recursion.

List iterators must be decremented.

You cannot compare iterators of the same container.

✅ Correct!

Correct! Because lists are not stored contiguously, the < operator is not defined; use != instead.

❌ Incorrect

The < operator is only defined for random-access iterators (like vector or deque).

QUESTION 5

Why would you call is.clear() before returning an istream& from a function?

To delete all data within the stream.

To reset the error state (like EOF) so the caller can continue using it.

To flush the output buffer.

To close the associated file handle.

✅ Correct!

Once a stream hits EOF, it remains in an error state. clear() resets the state bits.

❌ Incorrect

clear() affects the state flags, not the data contents or file connection.