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std::skipws, std::noskipws

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< cpp‎ | io‎ | manip
Revision as of 16:52, 2 November 2012 by P12bot (Talk | contribs)

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<td>
Defined in header <ios>
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<td></td> <td></td> <tr class="t-dcl ">

<td >
std::ios_base& skipws( std::ios_base& str );
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<td > (1) </td> <td class="t-dcl-nopad"> </td> </tr> <tr class="t-dcl ">

<td >
std::ios_base& noskipws( std::ios_base& str );
</td>

<td > (2) </td> <td class="t-dcl-nopad"> </td> </tr> Template:ddcl list end

Enables or disables skipping of leading whitespace by the formatted input functions (enabled by default). Has no effect on output.

1) enables the skipws flag in the stream str as if by calling str.setf(std::ios_base::skipws)

2) disables the skipws flag in the stream str as if by calling str.unsetf(std::ios_base::skipws)

The whitespace skipping is performed by the constructor of std::basic_istream::sentry, which reads and discards the characters classified as whitespace by the std::ctype facet of the stream's imbued locale.

This is an I/O manipulator, it may be called with an expression such as out << std::noskipws for any out of type std::basic_ostream or with an expression such as in >> std::noskipws for any in of type std::basic_istream.

Contents

Parameters

str - reference to I/O stream

Return value

str (reference to the stream after manipulation)

Example

#include <iostream>
#include <sstream>
int main()
{
    char c1, c2, c3;
    std::istringstream("a b c") >> c1 >> c2 >> c3;
    std::cout << "Default  behavior: c1 = " << c1 << " c2 = " << c2 << " c3 = " << c3 << '\n';
    std::istringstream("a b c") >> std::noskipws >> c1 >> c2 >> c3;
    std::cout << "noskipws behavior: c1 = " << c1 << " c2 = " << c2 << " c3 = " << c3 << '\n';
}

Output:

Default  behavior: c1 = a c2 = b c3 = c
noskipws behavior: c1 = a c2 =   c3 = b

See also

Template:cpp/io/manip/dcl list resetiosflagsTemplate:cpp/io/manip/dcl list setiosflags