#include <stdio.h>

#include "shared.h"

double altitude = 900.0; // we start high

double speed = 200.0;    // mph. not exported, not visible 

// greeting() is an exported function and is globally visible
void greeting(void)
{
   printf("Hi, nice to meet you!\n");

   return;
}

// print_altitude() -- prints current altitude, exported through "shared.h"
void print_altitude(void)
{
   printf("Current altitude is: %g\n", altitude);

   return;
}

// ascend() -- increase altitude. Declared static, and is not visible from other files
static void ascend(double dz)
{
   altitude += dz;
}

// descend() -- decrease altitude. Not exported, but still visible
void descend(double dz)
{
   ascend(-dz);
}