How to go to the beginning of the file in fstream?

Question

I'm practicing file handling. I made a text file and wrote some characters in it, now I want the cursor to go to the beginning of the file and put a character there using seekp.

Here is the code

fstream ofile;

char ch = 'g';

ofile.open("test.txt", ios::out | ios::app);

ofile.seekp(0, ios::beg);
ofile.put(ch);

ofile.close();

Expected Result: It writes g at the start of file.

Actual Result: It appends g at the end.

I tried removing the ios::app tag but ios::out alone truncates the file before writing anything.

https://stackoverflow.com/questions/10359702/c-filehandling-difference-between-iosapp-and-iosate?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa — drescherjm, May 15 '18 at 21:56
possible workaround: https://stackoverflow.com/questions/7300306/c-overwriting-data-in-a-file-at-a-particular-position — NathanOliver, May 15 '18 at 21:58

score -1 · Answer 1 · answered May 15 '18 at 22:01

-1

See: http://en.cppreference.com/w/cpp/io/basic_fstream/open

std::ios::app seek to the end of stream before each write

answered May 15 '18 at 22:01

Gábor Buella

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How to go to the beginning of the file in fstream?

1 Answers1