std::round, std::lround, std::llround

From Cppreference

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Defined in header <cmath>
int round( float arg );		(since C++11)
int round( double arg );		(since C++11)
int round( long double arg );		(since C++11)
long lround( float arg );		(since C++11)
long lround( double arg );		(since C++11)
long lround( long double arg );		(since C++11)
long long llround( float arg );		(since C++11)
long long llround( double arg );		(since C++11)
long long llround( long double arg );		(since C++11)

Computes nearest integer to arg. Number is rounded away from zero in halfway cases

[edit] Parameters

arg

-

floating point value

[edit] Return value

nearest integer to arg.

[edit] See also

floor	nearest integer not greater than the given value (function)
ceil	nearest integer not less than the given value (function)
trunc (C++11)	nearest integer not greater in magnitude than the given value (function)