/* timedil.c -- 100126 (sjd)
      Demonstrate time dilation at different velocities
*/

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

#define  C  +3.0e8    /* speed of light in m/s */

void splash(void);
double tdiff(double v);

int main()
{
   double vel;       /* velocity in c */
   double dt;        /* difference between moving clock and clock at rest */
   
   splash();
   
   printf("   Velocity    Earth hours/spaceship hour\n");
   printf("   --------------------------------------\n");
   
   for (vel = 0.1; vel < 0.999; vel += 0.1) {
      printf("   %5.1fc%21.3f\n", vel, tdiff(vel));
   }
   
   printf("\n");
   system("pause");
   return 0;
}

/* displays program splash screen */
void splash()
{
   printf("This program displays the hours elapsed on a clock\n"
          "on earth compared to a clock on a spaceship moving\n"
          "at the velocity shown.\n\n");
}
          
/* returns time dilation at vel v (given in tems of c) */
double tdiff(double v)
{  
   return 1.0 / sqrt(1.0 - ((v * C) * (v * C)) / ( C * C));
}