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std::dec, std::hex, std::oct

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< cpp‎ | io‎ | manip
Revision as of 23:03, 31 May 2013 by P12bot (Talk | contribs)

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Defined in header <ios>
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Modifies the default numeric base for integer I/O

1) sets the basefield of the stream str to dec as if by calling str.setf(std::ios_base::dec, std::ios_base::basefield)

2) sets the basefield of the stream str to hex as if by calling str.setf(std::ios_base::hex, std::ios_base::basefield)

3) sets the basefield of the stream str to oct as if by calling str.setf(std::ios_base::oct, std::ios_base::basefield)

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

Contents

[edit] Parameters

str - reference to I/O stream

[edit] Return value

str (reference to the stream after manipulation)

[edit] Example

#include <iostream>
#include <sstream>
int main()
{
    std::cout << "The number 42 in octal:   " << std::oct << 42 << '\n'
              << "The number 42 in decimal: " << std::dec << 42 << '\n'
              << "The number 42 in hex:     " << std::hex << 42 << '\n';
    int n;
    std::istringstream("2A") >> std::hex >> n;
    std::cout << std::dec << "Parsing \"2A\" as hex gives " << n << '\n';
}

Output:

The number 42 in octal:   52
The number 42 in decimal: 42
The number 42 in hex:     2a
Parsing "2A" as hex gives 42

[edit] See also

changes the base used for integer I/O
(function) [edit]
controls whether prefix is used to indicate numeric base
(function) [edit]