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Numeric array (valarray) | |||||||||||||||||||||||||||||||
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| Generic numeric operations | |||||||||||||||||||||||||||||||
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| C-style checked integer arithmetic | |||||||||||||||||||||||||||||||
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| Nearest integer floating point operations | |||||||||||||||||||||||||||||||||||||||||
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| Floating point manipulation functions | |||||||||||||||||||||||||||||||||||||||||
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| Classification and comparison | |||||||||||||||||||||||||||||||||||||||||
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| Macro constants | |||||||||||||||||||||||||||||||||||||||||
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Defined in header <cmath> | ||
| (1) | ||
float atan(float num); double atan(double num); | (until C++23) | |
/*floating-point-type*/ atan(/*floating-point-type*/ num); | (since C++23) (constexpr since C++26) | |
float atanf(float num); | (2) | (since C++11) (constexpr since C++26) |
longdouble atanl(longdouble num); | (3) | (since C++11) (constexpr since C++26) |
SIMD overload(since C++26) | ||
Defined in header <simd> | ||
template</*math-floating-point*/ V> constexpr/*deduced-simd-t*/<V> | (S) | (since C++26) |
Additional overloads(since C++11) | ||
Defined in header <cmath> | ||
template<class Integer> double atan( Integer num); | (A) | (constexpr since C++26) |
std::atan for all cv-unqualified floating-point types as the type of the parameter.(since C++23)S) The SIMD overload performs an element-wise std::atan onv_num.
| (since C++26) |
A) Additional overloads are provided for all integer types, which are treated asdouble. | (since C++11) |
Contents |
| num | - | floating-point or integer value |
| π |
| 2 |
| π |
| 2 |
If a range error occurs due to underflow, the correct result (after rounding) is returned.
Errors are reported as specified inmath_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
POSIX specifies that in case of underflow,num is returned unmodified, and if that is not supported, an implementation-defined value no greater thanDBL_MIN,FLT_MIN, andLDBL_MIN is returned.
The additional overloads are not required to be provided exactly as(A). They only need to be sufficient to ensure that for their argumentnum of integer type,std::atan(num) has the same effect asstd::atan(static_cast<double>(num)).
#include <cmath>#include <iostream> int main(){std::cout<<"atan(1) = "<< std::atan(1)<<'\n'<<"4*atan(1) = "<<4* std::atan(1)<<'\n'; // special valuesstd::cout<<"atan(Inf) = "<< std::atan(INFINITY)<<'\n'<<"2*atan(Inf) = "<<2* std::atan(INFINITY)<<'\n'<<"atan(-0.0) = "<< std::atan(-0.0)<<'\n'<<"atan(+0.0) = "<< std::atan(0)<<'\n';}
Output:
atan(1) = 0.7853984*atan(1) = 3.14159atan(Inf) = 1.57082*atan(Inf) = 3.14159atan(-0.0) = -0atan(+0.0) = 0
(C++11)(C++11) | computes arc sine (\({\small\arcsin{x}}\)arcsin(x)) (function)[edit] |
(C++11)(C++11) | computes arc cosine (\({\small\arccos{x}}\)arccos(x)) (function)[edit] |
(C++11)(C++11) | arc tangent, using signs to determine quadrants (function)[edit] |
(C++11)(C++11) | computes tangent (\({\small\tan{x}}\)tan(x)) (function)[edit] |
(C++11) | computes arc tangent of a complex number (\({\small\arctan{z}}\)arctan(z)) (function template)[edit] |
| applies the functionstd::atan to each element of valarray (function template)[edit] | |
C documentation foratan | |
