C library functions - atan2 ()

C standard library - <math.h>

description

C library functionsdouble atan2 (doubly y, double x ) Returns the yexpressed in radians/ xarctangent. Symbol values ​​y and x determine the correct quadrant.

statement

The following is a statement atan2 () function.

double atan2(doubly y, double x)

parameter

• x - x coordinate on behalf of floating-point values.
• y - y-axis represents the coordinates of floating-point values.

return value

This function returns the y expressed in radians / x arctangent, in radians interval [-pi, + pi].

Examples

The following example demonstrates the atan2 () function is used.

#include <stdio.h>
#include <math.h>

#define PI 3.14159265

int main ()
{
   double x, y, ret, val;

   x = -7.0;
   y = 7.0;
   val = 180.0 / PI;

   ret = atan2 (y,x) * val;
   printf("x = %lf, y = %lf 的反正切", x, y);
   printf("是 %lf 度\n", ret);
  
   return(0);
}

Let's compile and run the above program, which will result in the following:

x = -7.000000, y = 7.000000 的反正切是 135.000000 度

C standard library - <math.h>