std::setfill(3)

💖 std::setfill(3) — C++ Standard Library 💖

okay so this is the manual page for std::setfill, and yes the NAME is literally std::setfill — std::setfill. iconic, no notes. 💅

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🎀 NAME 🎀

std::setfill — std::setfill

✨ Synopsis ✨

Defined in header <iomanip>:

template< class CharT >
/*unspecified*/ setfill( CharT c );

When it’s used in an expression like out << setfill(c), it sets the fill character of the stream out to c. slay ✨

🌸 Parameters 🌸

• c — new value for the fill character. that’s the whole parameter, bestie 🫶

💫 Return value 💫

An object of unspecified type such that:

• if out is an object of type std::basic_ostream<CharT, Traits>, the expression out << setfill(c)
  • has type std::basic_ostream<CharT, Traits>&
  • has value out
  • behaves as if it called f(out, c)

where the function f is defined as:

template<class CharT, class Traits>
void f(std::basic_ios<CharT, Traits>& str, CharT c)
{
    // set fill character
    str.fill(c);
}

lowkey important: the return type is unspecified, so don’t go trying to name it, okay? iykyk 💀

🦋 Notes 🦋

The current fill character may be obtained with std::ostream::fill. tiny but useful 🍓

🌈 Example 🌈

Run this code, bestie:

#include <iomanip>
#include <iostream>

int main()
{
    std::cout << "default fill: [" << std::setw(10) << 42 << "]\n"
              << "setfill('*'): [" << std::setfill('*')
                                   << std::setw(10) << 42 << "]\n";
}

⭐ Output ⭐

default fill: [        42]
setfill('*'): [********42]

🩹 Defect reports 🩹

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

• DR: LWG 183
• Applied to: C++98
• Behavior as published: setbase could only be used with streams of type std::ostream
• Correct behavior: usable with any output character stream

look at that glow-up ✨

👀 See also 👀

• fill — manages the fill character (public member function of std::basic_ios<CharT,Traits>)
• internal — sets the placement of fill characters
• left — (function)
• right — (function)
• setw — changes the width of the next input/output field (function)

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okay that’s the whole page, bestie 💅 — the footer energy is from http://cppreference.com, version 2024.06.10, and this is the std::setfill(3) page. mwah 🫶💖