c++ 파일 입출력 (fstream)

#include <fstream>

 

파일에 출력하기 - ofstream

 ofstream 변수선언;

ex)

ofstream val("filename");

---------- or ----------

ofstream val;

val.open("filename")

 

val << "Hello world";   //<-해당 파일에 "Hello world"가 기록된다.

 

 

파일에 입력하기 - ifstream

 ifstream 변수선언;

ex)

ifstream val("filename");

---------- or ----------

ifstream val;

val.open("filename")

 

val >> buf;   //<-해당 파일에서 한 단어를 buf에 입력한다.

파일 사용후 .close()해준다.

Public members

(constructor)

             Construct object and optionally open file (constructor member)

rdbuf

Get the associated filebuf object (public member function )

is_open

Check if a file is open (public member function)

open

Open file (public member function )

close

Close file (public member function)

Members inherited from istream

operator>>

Extract formatted data (public member function )

gcount

Get number of characters extracted by last unformatted input operation (public member function)

get

Get unformatted data from stream (public member function )

getline

Get line from stream (public member function )

ignore

Extract and discard characters (public member functions)

peek

Peek next character (public member function )

read

Read block of data (public member function)

readsome

Read block of data available in the buffer (public member function )

putback

Put character back (public member function )

unget

Decrement get pointer (public member function )

tellg

Get position of the get pointer. (public member function )

seekg

Set position of the get pointer (public member function )

sync

Synchronize input buffer with source of characters (public member function)

sentry

Perform exception safe prefix/suffix operations (public member class)

 

Members inherited from ostream

operator<<

Insert data with format (public member function )

put

Put character (public member function)

write

Write block of data (public member function )

tellp

Get position of put pointer (public member function)

seekp

Set position of put pointer (public member function )

flush

Flush output stream buffer (public member function)

sentry

Perform exception safe prefix/suffix operations (public member classes)

 

Member functions inherited from ios

good

Check if the state of the stream is good for i/o operations. (public member function)

eof

Check if eofbit is set (public member function)

fail

Check if either failbit or badbit is set (public member function )

bad

Check if badbit is set (public member function)

operator!

Evaluate stream object (public member function)

operator void*

Convert to pointer (public member function)

rdstate

Get error state flags (public member function)

setstate

Set error state flag (public member function)

clear

Set error state flags (public member function)

copyfmt

Copy formatting information (public member functions)

fill

Get/set the fill character (public member function)

exceptions

Get/set exception mask (public member function)

imbue

Imbue locale (public member function)

tie

Get/set the tied stream (public member function)

narrow

Narrow character (public member function)

widen

Widen character (public member function)

 

Member functions inherited from ios_base

flags

Get/set format flags (public member function)

setf

Set specific format flags (public member function)

unsetf

Clear specific format flags (public member function)

precision

Get/Set floating-point decimal precision (public member function )

width

Get/set field width (public member function)

imbue

Imbue locale (public member function)

getloc

Get current locale (public member function)

xalloc

Return a new index for the internal extensible array [static] (public static member function)

iword

Get reference to integer element of the internal extensible array (public member function)

pword

Get reference to pointer of the internal extensible array (public member function)

register_callback

Register event callback function (public member function)

sync_with_stdio

Activate/deactivate synchronization of iostream and cstdio streams [static] (public static member function)

Reference : http://www.cplusplus.com/reference/iostream/fstream/