std::dec,std::hex,std::oct(3)

💅 std::dec, std::hex, std::oct 💅

okay so bestie, welcome to the C++ Standard Libary manual page for std::dec, std::hex, and std::oct — manual section (3) energy. The page is literally named std::dec,std::hex,std::oct, and it's here to make your integer I/O switch bases like a main character. 👑

🌸 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)

These cuties modify 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, bestie. 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. That's the whole parameter, and she's doing her job. 🫶

🦋 Return value 🦋

str (reference to the stream after manipulation). It hands the stream right back to you, freshly manipulated and glowing. ✨

🌈 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

👑 See also 👑

• setbase — changes the base used for integer I/O (function)
• showbase — controls whether prefix is used to indicate numeric base
• noshowbase — (function)

xoxo, your Unix bestie 💖 this page came from http://cppreference.com, version/date 2024.06.10, and the manual is std::dec,std::hex,std::oct(3) — periodt. 🎀