119 lines
6.3 KiB
Markdown
119 lines
6.3 KiB
Markdown
[std.manip]
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# 31 Input/output library [[input.output]](./#input.output)
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## 31.7 Formatting and manipulators [[iostream.format]](iostream.format#std.manip)
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### 31.7.7 Standard manipulators [std.manip]
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7192)
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The header [<iomanip>](iomanip.syn#header:%3ciomanip%3e "31.7.3 Header <iomanip> synopsis [iomanip.syn]") defines several functions that support
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extractors and inserters that alter information maintained by classios_base and its derived classes[.](#1.sentence-1)
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[ð](#lib:resetiosflags)
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`unspecified resetiosflags(ios_base::fmtflags mask);
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`
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7203)
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*Returns*: An object of
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unspecified type such that if out is an object of typebasic_ostream<charT, traits> then the expressionout << resetiosflags(mask) behaves as if it calledf(out, mask), or if in is an object of typebasic_istream<charT, traits> then the expressionin >> resetiosflags(mask) behaves as if it calledf(in, mask), where the function f is defined as:[291](#footnote-291 "The expression cin >> resetiosflags(ios_base::skipws) clears ios_base::skipws in the format flags stored in the basic_istream<charT, traits> object cin (the same as cin >> noskipws), and the expression cout << resetiosflags(ios_base::showbase) clears ios_base::showbase in the format flags stored in the basic_ostream<charT, traits> object cout (the same as cout << noshowbase).")void f(ios_base& str, ios_base::fmtflags mask) {// reset specified flags str.setf(ios_base::fmtflags(0), mask);}
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The expression out << resetiosflags(mask) has
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type basic_ostream<charT, traits>& and value out[.](#2.sentence-2)
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The
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expression in >> resetiosflags(mask) has typebasic_istream<charT, traits>& and value in[.](#2.sentence-3)
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[ð](#lib:setiosflags)
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`unspecified setiosflags(ios_base::fmtflags mask);
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`
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7242)
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*Returns*: An object of unspecified type such that ifout is an object of typebasic_ostream<charT, traits> then the expressionout << setiosflags(mask) behaves as if it calledf(out, mask),
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or ifin is an object of typebasic_istream<charT, traits> then the expressionin >> setiosflags(mask) behaves as if it calledf(in, mask), where the function f is defined as:
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[ð](#lib:fmtflags,ios_base)
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void f(ios_base& str, ios_base::fmtflags mask) {// set specified flags str.setf(mask);}
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The expressionout << setiosflags(mask) has typebasic_ostream<charT, traits>& and valueout[.](#3.sentence-2)
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The expressionin >> setiosflags(mask) has typebasic_istream<charT, traits>& and valuein[.](#3.sentence-3)
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[ð](#lib:setbase)
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`unspecified setbase(int base);
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`
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[4](#4)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7288)
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*Returns*: An object of unspecified type such that ifout is an object of typebasic_ostream<charT, traits> then the expressionout << setbase(base) behaves as if it calledf(out, base),
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or ifin is an object of typebasic_istream<charT, traits> then the expressionin >> setbase(base) behaves as if it calledf(in, base), where the function f is defined as:void f(ios_base& str, int base) {// set basefield str.setf(base == 8 ? ios_base::oct : base == 10 ? ios_base::dec : base == 16 ? ios_base::hex : ios_base::fmtflags(0), ios_base::basefield);}
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The expressionout << setbase(base) has typebasic_ostream<charT, traits>& and valueout[.](#4.sentence-2)
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The expressionin >> setbase(base) has typebasic_istream<charT, traits>& and valuein[.](#4.sentence-3)
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[ð](#lib:setfill)
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`unspecified setfill(char_type c);
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`
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[5](#5)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7336)
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*Returns*: An object of unspecified type such that ifout is an object of typebasic_ostream<charT, traits> and c has typecharT then the expressionout << setfill(c) behaves as if it calledf(out, c), where the function f is defined as:template<class charT, class traits>void f(basic_ios<charT, traits>& str, charT c) {// set fill character str.fill(c);}
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The expressionout << setfill(c) has typebasic_ostream<charT, traits>& and valueout[.](#5.sentence-2)
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[ð](#lib:setprecision)
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`unspecified setprecision(int n);
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`
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[6](#6)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7370)
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*Returns*: An object of unspecified type such that ifout is an object of typebasic_ostream<charT, traits> then the expressionout << setprecision(n) behaves as if it calledf(out, n),
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or ifin is an object of typebasic_istream<charT, traits> then the expressionin >> setprecision(n) behaves as if it calledf(in, n), where the function f is defined as:void f(ios_base& str, int n) {// set precision str.precision(n);}
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The expressionout << setprecision(n) has typebasic_ostream<charT, traits>& and valueout[.](#6.sentence-2)
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The expressionin >> setprecision(n) has typebasic_istream<charT, traits>& and valuein[.](#6.sentence-3)
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[ð](#lib:setw)
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`unspecified setw(int n);
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`
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[7](#7)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L7415)
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*Returns*: An object of unspecified type such that ifout is an instance ofbasic_ostream<charT, traits> then the expressionout << setw(n) behaves as if it calledf(out, n),
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or ifin is an object of typebasic_istream<charT, traits> then the expressionin >> setw(n) behaves as if it calledf(in, n), where the function f is defined as:void f(ios_base& str, int n) {// set width str.width(n);}
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The expressionout << setw(n) has typebasic_ostream<charT, traits>& and valueout[.](#7.sentence-2)
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The expressionin >> setw(n) has typebasic_istream<charT, traits>& and valuein[.](#7.sentence-3)
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[291)](#footnote-291)[291)](#footnoteref-291)
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The expression cin >> resetiosflags(ios_base::skipws) clears ios_base::skipws in the format flags stored in thebasic_istream<charT, traits> object cin (the same ascin >> noskipws), and the expressioncout << resetiosflags(ios_base::showbase) clears ios_base::showbase in the
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format flags stored in the basic_ostream<charT, traits> objectcout (the same as cout << noshowbase)[.](#footnote-291.sentence-1)
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