#include <stdio.h>
#include <math.h>
#define FILENAME "balloon1.txt"
int main(void)
{
/* Declare variables. */
double start_time_hour, start_time_minute, end_time_hour, end_time_minute, time_passed_hour, time_passed_minute;
double incre_min, total_time, time_incre, alt, vel, max_alt, max_time_of_alt;
FILE *balloon;
/* Open output file. */
balloon = fopen(FILENAME,"w");
/* Get user input from the keyboard. */
do
{
printf("Enter start time of weather balloon release in hrs then min. \n");
printf("start time: \n");
scanf("%lf %lf", &start_time_hour, &start_time_minute);
printf("\nEnter final time of weather balloon traveling in hrs then min. \n");
printf("final time: \n");
scanf("%lf %lf",&end_time_hour, &end_time_minute);
/* Determine length of time passed based on user inputted times */
time_passed_hour = end_time_hour - start_time_hour;
time_passed_minute = end_time_minute - start_time_minute;
total_time = time_passed_hour + (time_passed_minute / 60);
/* Checks data entered to see if valid */
if (end_time_hour < start_time_hour)
{
printf("\nStart time is greater than final time. Please reenter time values again.\n\n");
}
if (end_time_hour > 48)
{
printf("\nFinal time value cannot be greater than 48 hours. Please reenter time values again.\n\n");
}
} while (end_time_hour < start_time_hour || (end_time_hour > 48));
printf("\nEnter time increment in minutes.\n");
printf("time increment: \n");
scanf("%lf",&incre_min);
double unceil_step = (total_time * 60) / incre_min;
double steps = ceil((total_time * 60) / incre_min);
/* Determine altitudes and velocites of balloon */
fprintf(balloon,"(time(hrs)) (alitude(m)) (velocity(m/s))\n");
for (double k = 0; k <= steps; k++)
{
double T = (k*(total_time/unceil_step)) + start_time_hour;
alt = -0.12*pow(T,4) + 12*pow(T,3) - 380*pow(T,2) + 4100*T + 220;
vel = -0.48*pow(T,3) + 36*pow(T,2) - 760*T + 4100;
if(alt > max_alt)
{
max_alt = alt;
max_time_of_alt = T;
};
fprintf(balloon,"%.3lf %.3lf %.3lf\n", T, alt, vel/3600);
}
fprintf(balloon, "\nmax alitude: %.3lf m\n", max_alt);
fprintf(balloon, "\ntime of max alitude: %.3lf hrs\n", max_time_of_alt);
fclose(balloon);/* Close file and exit . */
return 0;
}
