C atan2() function

C atan2() function - Calculate Arctangent


double atan2(double y, double x)

The atan2() function is used to calculate the arctangent of y/x.


Name Description Required /Optional
x Represent x-coordinate. Required
y Represent y-coordinate. Required

Return value from atan2()

  • Returns a value in the range -π to π radians.
  • Returns a value of 0 if both arguments of the atan2() function are zero.

Example: atan2() function

The following example shows the usage of atan2() function.

#include <stdio.h>
#include <math.h> 
int main(void)
    double x, y, z;
    x = 0.45;
    y = 0.23;
    z = atan2(x,y);    
    printf("atan2( %lf, %lf ) = %lf", x, y, z); 


atan2( 0.450000, 0.230000 ) = 1.098299

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