Calculating moment, using (Q) kg * (D) m = (M) kgm.

wam.c

#include <stdio.h>
#include <stdlib.h>

typedef enum {FALSE, TRUE} BOOLEAN;

void usage(char *program)
{
	printf("Usage:\n");
	printf("\tExample: %s 0 50 0.6\n\n", program);
	printf("First argument is moment. (kgm)\n");
	printf("Second argument is weight. (kg)\n");
	printf("Third argument is arm. (m)\n\n");
}

/*
 * moment = weight * arm
 * weight = moment / arm
 * arm    = moment / weight
 */
BOOLEAN calculate(double *moment, double *weight, double *arm)
{
	if (*moment <= 0 && *weight > 0 && *arm > 0) {
		printf("Calculating moment...\n");
		*moment = *weight * *arm;
	} else if (*moment > 0 && *weight <= 0 && *arm > 0) {
		printf("Calculating weight...\n");
		*weight = *moment / *arm;
	} else if (*moment > 0 && *arm <= 0 && *weight > 0) {
		printf("Calculating arm...\n");
		*arm = *moment / *weight;
	} else {
		return FALSE;
	}

	return TRUE;
}
	
/*
 * EUR-1 pallets weighs between 22-25 kg depending on if the
 * pallet is dry or wet.
 *
 * An EUR-1 pallet is 800mm x 1200mm.
 * When taken from the short side, the balance point becomes
 * 1200mm / 2, if load is evenly placed or centered.
 *
 * So let us say the load is 75kg, including the pallet - of course.
 * It would be 75.0 (kg) * 0.6 (m) = moment in kgm.
 */
int main(int argc, char *argv[])
{
	double moment, weight, arm;
	BOOLEAN success;

	if (argc != 4) {
		usage(argv[0]);

		printf("Printing arguments:\n\n");
		printf("argv[0] = %s\n", argv[0]);
		printf("argv[1] (Moment) = %s\n", argv[1]);
		printf("argv[2] (Weight) = %s\n", argv[2]);
		printf("argv[3]    (Arm) = %s\n", argv[3]);
		return EXIT_FAILURE;
	}

	moment = atof(argv[1]);
	weight = atof(argv[2]);
	arm = atof(argv[3]);

	success = calculate(&moment, &weight, &arm);

	if (success) {
		printf("Calculation is done...\n\n");
		printf("Moment:\t %.2f kgm.\n", moment);
		printf("Weight:\t %.2f kg.\n", weight);
		printf("   Arm:\t %.2f m.\n", arm);
		return EXIT_SUCCESS;
	} else {
		printf("Something went wrong...\n");
		printf("You need to at least know 2 of the 3 values.\n\n");
		printf("Moment:\t %.2f kgm.\n", moment);
		printf("Weight:\t %.2f kg.\n", weight);
		printf("   Arm:\t %.2f m.\n", arm);

		usage(argv[0]);

		return EXIT_FAILURE;
	}
}