std::atan2

 

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Defined in header <cmath>
float       atan2( float y, float x );	(1)
double      atan2( double y, double x );	(2)
long double atan2( long double y, long double x );	(3)
Promoted    atan2( Arithmetic y, Arithmetic x );	(4)	(since C++11)

Computes the inverse tangent of y/x using the signs of arguments to correctly determine quadrant.

4) If any argument has integral type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double.

Parameters

x, y

-

floating point value

Return value

Arc tangent of y/x in radians in the range of [-π; π] radians.

Y argument

Return value

X argument

Example

#include <cmath>
#include <utility>
#include <iostream>
 
std::pair<double, double> cartesian_to_polar(double x, double y)
{
    return {std::hypot(x, y), std::atan2(y,x)};
}
 
int main()
{
    std::pair<double, double> polar = cartesian_to_polar(1, 1);
    std::cout << "(1,1) cartesian is (" << polar.first
               << "," << polar.second<< ") polar\n";
}

Output:

(1,1) cartesian is (1.41421,0.785398) polar

See also

atan	computes arc tangent (arctan(x)) (function)
asin	computes arc sine (arcsin(x)) (function)
acos	computes arc cosine (arccos(x)) (function)
tan	computes tangent (tan(x)) (function)