What is the output of the code segment below? Assume all necessary libraries have been included.

Question

fstream train;

train.open("TTR_Rules.txt", ios::in|ios::out);

char ch;

train.seekp(10, ios::beg);

train.seekg(-2, ios::cur);

train.seekp(10 + train.tellg() - 3);

train.get(ch);

cout << ch;

The contents of the file (TTR_Rules.txt) are as follows. There are no new line characters in the file.

Ticket to Ride is a cross-country train adventure. Players compete to connect different cities by laying claim to railway routes on a map of North America.

a) i

b) a

c) s

d) n

Answer 1

Hello, Ethan,

Rather than provide the answer, I'll help you figure it out. The statements which drive the answer are:

train.seekp(10, ios::beg)

train.seekg(-2, ios::cur);

train.seekp(10 + train.tellg() - 3);

train.get(ch);

These statements affect which character will be read by the last statement, above, the `train.get(ch)`. Note that, since the `train` stream has been opened for both input and output, the use of either (or, as in the code here, both) seekp() and seekg(), or tellp() and tellg(), should have the same effect. (The 'p' and 'g' versions are interchangeable, because there's only 1 'cursor' for the file)..

So:

1. `train.seekp(10, ios::beg)` sets the file cursor to 10 (from the beginning).
2. `train.seekg(-2, ios::cur)` sets the file cursor to 2 before its current location (i.e. 10 - 2), or 8.
3. `train.seekp(10 + train.tellg() - 3)` sets the file cursor to position 10 + the current location - 3 (i.e. 10 + 8 - 3), or 15.
4. Finally, `train.get(c)` reads the character at location 15, and leaves the cursor at location 16.