rad2deg.c

C语言库函数的源代码,是C语言学习参考的好文档。

/* +++Date last modified: 05-Jul-1997 */

/*
**  RAD2DEG.C - Functions to convert between radians and degrees
*/

#include <math.h>
#include "snipmath.h"

#undef rad2deg                /* These are macros defined in PI.H */
#undef deg2rad

double rad2deg(double rad)
{
      return (180.0 * rad / (PI));
}

double deg2rad(double deg)
{
      return (PI * deg / 180.0);
}

#ifdef TEST

#include <stdio.h>

main()
{
      double X;

      for (X = 0.0; X <= 360.0; X += 45.0)
            printf("%3.0f degrees = %.12f radians\n", X, deg2rad(X));
      puts("");
      for (X = 0.0; X <= (2 * PI + 1e-6); X += (PI / 6))
            printf("%.12f radians = %3.0f degrees\n", X, rad2deg(X));
      return 0;
}

#endif /* TEST */