/*
 * Program to calculate Acme's price for ball caps, as described
 * in the homework writeup.
 */
#include <stdio.h>

int main(void) {

	int caps;
	printf("how many caps?\n");
	if (scanf("%d", &caps) != 1) {
		printf("invalid input (not integer)\n");
		return 1;
	}
	if (caps <= 0) {
		printf("invalid input (not positive)\n");
		return 1;
	}

	if (caps <= 50) {
		printf("price $%d\n", 100);
		if (caps < 50) {
			printf("you could get 50 caps for the same price\n");
		}
	}
	else if (caps <= 200) {
        /* how many groups of 5, in addition to the minimum? */
		int groups = (caps - 50) / 5;
		int price = 100 + (groups * 5);
		if ((caps % 5) != 0) {
			price += 5;
		}
		printf("price $%d\n", price);
		if ((caps % 5) != 0) {
			/* trick to round up to next multiple of 5 */
			printf("you could get %d caps for the same price\n", 
					((caps + 5-1) / 5) * 5);
		}
	}
	else {
		printf("you qualify for the volume discount!\n");
		int discount_groups = (caps - 200) / 5;
		int price = 
			/* cost for first 50 caps */
			100 + 
			/* cost for next 150 caps */
			150 +
			/* cost for remaining caps (almost) */
			discount_groups * 4;
		if ((caps % 5) != 0) {
			price += 4;
		}
		printf("price $%d\n", price);
		if ((caps % 5) != 0) {
			/* trick to round up to next multiple of 5 */
			printf("you could get %d caps for the same price\n", 
					((caps + 5-1) / 5) * 5);
		}
	}

	return 0;
}