Input/output manipulators
From cppreference.com
                    
                                        
                    
                    
                                                            
                    Manipulators are helper functions that make it possible to control input/output streams using operator<< or operator>>.
The manipulators that are invoked without arguments (e.g. std::cout << std::boolalpha; or std::cin >> std::hex;) are implemented as functions that take a reference to a stream as their only argument. The special overloads of basic_ostream::operator<< and basic_istream::operator>> accept pointers to these functions.
The manipulators that are invoked with arguments (e.g. std::cout << std::setw(10);) are implemented as functions returning objects of unspecified type.  These manipulators define their own operator<< or operator>> which perform the requested manipulation.
|   Defined in header  
<ios>  | 
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|    switches between textual and numeric representation of booleans  (function)  | 
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|    controls whether prefix is used to indicate numeric base   (function)  | 
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|    controls whether decimal point is always included in floating-point representation   (function)  | 
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   controls whether the + sign used with non-negative numbers (function)  | 
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|    controls whether leading whitespace is skipped on input  (function)  | 
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|    controls whether uppercase characters are used with some output formats   (function)  | 
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|    controls whether output is flushed after each operation  (function)  | 
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|    sets the placement of fill characters    (function)  | 
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|    changes the base used for integer I/O  (function)  | 
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|    (C++11)(C++11) 
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   changes formatting used for floating-point I/O  (function)  | 
|   Defined in header  
<istream>  | 
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|    consumes whitespace  (function template)  | 
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|   Defined in header  
<ostream>  | 
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|    outputs '\0'  (function template)  | 
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|    flushes the output stream  (function template)  | 
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|    outputs '\n' and flushes the output stream  (function template)  | 
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|   Defined in header  
<iomanip>  | 
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|    clears the specified ios_base flags  (function)  | 
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|    sets the specified ios_base flags  (function)  | 
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|    changes the base used for integer I/O  (function)  | 
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|    changes the fill character  (function template)  | 
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|    changes floating-point precision  (function)  | 
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|    changes the width of the next input/output field  (function)  | 
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|    (C++11) 
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   parses a monetary value   (function template)  | 
|    (C++11) 
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   formats and outputs a monetary value  (function template)  | 
|    (C++11) 
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   parses a date/time value of specified format  (function template)  | 
|    (C++11) 
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   formats and outputs a date/time value according to the specified format  (function template)  | 
|    (C++14) 
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   inserts and extracts quoted strings with embedded spaces   (function template)  |