std::dec, std::hex, std::oct
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C++
Input/output library
| I/O manipulators | ||||
| Print functions (C++23) | ||||
| C-style I/O | ||||
| Buffers | ||||
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(C++98/26*) | ||||
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| Streams | ||||
| Abstractions | ||||
| File I/O | ||||
| String I/O | ||||
| Array I/O | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
| Synchronized Output | ||||
(C++20) | ||||
| Types | ||||
| Error category interface | ||||
(C++11) | ||||
(C++11) |
Input/output manipulators
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| Status flags manipulation | |||||||||||||||||||||||||||||||
| Time and money I/O | |||||||||||||||||||||||||||||||
| Quoted manipulator | |||||||||||||||||||||||||||||||
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| Defined in header <ios>
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| std::ios_base& dec( std::ios_base& str ); |
(1) | |
| std::ios_base& hex( std::ios_base& str ); |
(2) | |
| std::ios_base& oct( std::ios_base& str ); |
(3) | |
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
Run this code
#include <bitset> #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'; / the output base is sticky until changed std::cout << std::hex << "42 as hex gives " << 42 << " and 21 as hex gives " << 21 << '\n'; / Note: there is no I/O manipulator that sets up a stream to print out / numbers in binary format (e.g. bin). If binary output is necessary / the std::bitset trick can be used: std::cout << "The number 42 in binary: " << std::bitset<8>{42} << '\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 42 as hex gives 2a and 21 as hex gives 15 The number 42 in binary: 00101010
[edit] See also
| changes the base used for integer I/O (function) [edit] | |
| controls whether prefix is used to indicate numeric base (function) [edit] |
