Simple ifstream Question

Can you use the same ifstream on multiple files?

Example:

ifstream input_file( "file.txt" );
input_file.close();
ifstream input_file( "file2.txt" );

This gives an error.

Is there any way to make it work?

You should call clear() as well after close().

gg

You can't declare two variables of the same name in the same scope. So the second one would just need to be an open call, not a constructor.

But there probably isn't much reason to go through all the trouble of reusing the fstream.

Originally Posted by Codeplug

You should call clear() as well after close().

gg

Originally Posted by tabstop

You can't declare two variables of the same name in the same scope. So the second one would just need to be an open call, not a constructor.

Yeah woops, I mistyped. Here's what I have now:

Code:

ifstream input_file( "file.txt" );
input_file.close();
input_file.clear();

input_file( "file2.txt" ); // Line 57

But still,

Code:

ex2.cpp:57: error: expected `;' before ‘open’
ex2.cpp:57: warning: statement has no effect

Originally Posted by anon

But there probably isn't much reason to go through all the trouble of reusing the fstream.

I have to open about 20 files and do various things in each. Is there a way do reuse the same ifstream, or do I have to make 20 different ifstream variables?

Originally Posted by Paul22000

Yeah woops, I mistyped. Here's what I have now:

Code:

ifstream input_file( "file.txt" );
input_file.close();
input_file.clear();

input_file( "file2.txt" ); // Line 57

But still,

Code:

ex2.cpp:57: error: expected `;' before ‘open’
ex2.cpp:57: warning: statement has no effect

I have to open about 20 files and do various things in each. Is there a way do reuse the same ifstream, or do I have to make 20 different ifstream variables?

I don't see the word "open" in that last line. Why don't I?

Originally Posted by tabstop

I don't see the word "open" in that last line. Why don't I?

Woops

I did

Code:

ifstream input_file( "file.txt" );
input_file.close();
input_file.clear();

input_file open( "file2.txt" );

Originally Posted by Paul22000

Woops

I did

Code:

ifstream input_file( "file.txt" );
input_file.close();
input_file.clear();

input_file open( "file2.txt" );

Is that a direct copy-paste from the file? (If not, why not?) You need a dot between file and open.

Originally Posted by tabstop

You need a dot between file and open.

AH!!!!!!!!!!!!!!!!!!!!!

Lol

Thank you, works now