/* June 3, 1998 */
/* program to compute duration of flight and height of projectile */


#include 
#include 

#define G 32.17 /* Definition of G */

/* Function prototypes */
void instruct (void);
double get_time (double dist, double vel, double theta);
double get_height (double vel, double theta, double time);

main ()
{
	/* declarations */
	double theta, vel, dist, time, height;

	/* function call to display instructions */
	instruct();

	/* request for user's input */
	printf("Enter angle of elevation in radians> ");
        scanf("%lf", &theta);
        printf("Enter velocity in ft/sec> ");
        scanf("%lf", &vel);
        printf("Enter distance to target in ft> ");
        scanf("%lf", &dist);

	/* function call to display time */
	time = get_time(dist, vel, theta);
	printf(" \n");
	printf("Duration of flight is %.3f sec \n", time);

	/* function call to display height */
	height = get_height(vel, theta, time);
	printf(" \n");
	printf("Height above ground when it reaches target is %.3f ft \n", height);
}

/* function definition */

double
get_time (double dist, double vel, double theta)
{
	/* declaration */
	double time;

	/* computation */
	time = dist / (vel * cos(theta));
	return (time);
}

double
get_height(double vel, double theta, double time)
{
	/* declaration */
	double height;

	/* computation */
	height = vel * sin(theta) * time - ((G * time * time) / 2);
	return (height);
}

void
instruct(void)
{
	/* display instructions */
	printf(" \n");
	printf("Instructions \n");
	printf("------------ \n");
	printf("Input angle of elevation, distance and velocity \n");
	printf(" \n");
}

    Source: geocities.com/yosemite/rapids/9568

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