std::dec,std::hex,std::oct (3) - Linux Manuals

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

NAME

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

Synopsis

Defined in header <ios>
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.

Parameters

str - reference to I/O stream

Return value

str (reference to the stream after manipulation)

Example

// Run this code

  #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';
  }

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