Library: Input/output
A predefined stream that controls output to a stream buffer associated with the object stdout declared in <cstdio>
#include <iostream> namespace std { extern wostream wcout; }
The object wcout controls output to a stream buffer associated with the object stdout declared in <cstdio>. By default the standard C and C++ streams are synchronized, but performance can be improved by using the ios_base member function synch_with_stdio to desynchronize them.
After the object wcin is initialized, wcin.tie() returns &wcout, which implies that wcin and wcout are synchronized. wcout uses the locale codecvt facet to convert the wide characters it receives to the tiny characters it outputs to stdout.
The formatting is done through member functions or manipulators.
Manipulators | Member Functions |
showpos |
setf(ios_base::showpos) |
noshowpos |
unsetf(ios_base::showpos) |
showbase |
setf(ios_base::showbase) |
noshowbase |
unsetf(ios_base::showbase) |
uppercase |
setf(ios_base::uppercase) |
nouppercase |
unsetf(ios_base::uppercase) |
showpoint |
setf(ios_base::showpoint) |
noshowpoint |
unsetf(ios_base::showpoint) |
boolalpha |
setf(ios_base::boolalpha) |
noboolalpha |
unsetf(ios_base::boolalpha) |
unitbuf |
setf(ios_base::unitbuf) |
nounitbuf |
unsetf(ios_base::unitbuf) |
internal |
setf(ios_base::internal, ios_base::adjustfield) |
left |
setf(ios_base::left, ios_base::adjustfield) |
right |
setf(ios_base::right, ios_base::adjustfield) |
dec |
setf(ios_base::dec, ios_base::basefield) |
hex |
setf(ios_base::hex, ios_base::basefield) |
oct |
setf(ios_base::oct, ios_base::basefield) |
fixed |
setf(ios_base::fixed, ios_base::floatfield) |
scientific |
setf(ios_base::scientific, ios_base::floatfield) |
resetiosflags (ios_base::fmtflags flag) |
setf(0,flag) |
setiosflags (ios_base::fmtflags flag) |
setf(flag) |
setbase (int base) |
see above |
setfill(char_type c) |
fill(c) |
setprecision (int n) |
precision(n) |
setw (int n) |
width(n) |
endl |
|
ends |
|
flush |
flush( ) |
showpos |
Generates a + sign in nonnegative generated numeric output. |
showbase |
Generates a prefix indicating the numeric base of generated integer output |
uppercase |
Replaces certain lowercase letters with their uppercase equivalents in generated output |
showpoint |
Generates a decimal-point character unconditionally in generated floating-point output |
boolalpha |
Inserts and extracts bool type in alphabetic format |
unitbuf |
Flushes output after each output operation |
internal |
Adds fill characters at a designated internal point in certain generated output. If no such point is designated, it's identical to right. |
left |
Adds fill characters on the right (final positions) of certain generated output |
right |
Adds fill characters on the left (initial positions) of certain generated output |
dec |
Converts integer input or generates integer output in decimal base |
hex |
Converts integer input or generates integer output in hexadecimal base |
oct |
Converts integer input or generates integer output in octal base |
fixed |
Generates floating-point output in fixed-point notation |
scientific |
Generates floating-point output in scientific notation |
resetiosflags(ios_base::fmtflags flag) |
Resets the fmtflags field flag |
setiosflags(ios_base::fmtflags flag) |
Sets up the flag flag |
setbase(int base) |
Converts integer input or generates integer output in base base. The parameter base can be 8, 10 or 16. |
setfill(char_type c) |
Sets the character used to pad (fill) an output conversion to the specified field width |
setprecision(int n) |
Sets the precision (number of digits after the decimal point) to generate on certain output conversions |
setw(int n) |
Sets the field width (number of characters) to generate on certain output conversions |
endl |
Inserts a newline character into the output sequence and flush the output buffer. |
ends |
Inserts a null character into the output sequence. |
flush |
Flush the output buffer. |
precision() 6 width() 0 fill() the space character flags() skipws | dec getloc() locale::locale()
Keep in mind that while the manipulator endl flushes the stream buffer, outputting the character L'\n' is not guaranteed to flush the stream buffer. You should output the L'\n' character without endl only if you do not need the buffer flushed. Note that outputting the L'\n' character in such cases, and hence not forcing a buffer flush, may result in a performance improvement. It greatly improves performance when C and C++ streams are not synchronized.
basic_ostream, basic_iostream, basic_filebuf, cin, cout, cerr, clog, wcin, wcerr, wclog, ios_base, basic_ios
ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.3.2