/* ex_ch10_1.c -- rain.c modified to work with pointer math */
#include <stdio.h>
// number of months in a year
#define MONTHS 12
// number of years of data
#define YEARS 5

int main(void)
{
	// initializing rainfall data for 2000 - 2004
	const float rain[YEARS][MONTHS] =
	{
		{4.3, 4.3, 4.3, 3.0, 2.0, 1.2, 0.2, 0.2, 0.4, 2.4, 3.5, 6.6},
		{8.5, 8.2, 1.2, 1.6, 2.4, 0.0, 5.2, 0.9, 0.3, 0.9, 1.4, 7.3},
		{9.1, 8.5, 6.7, 4.3, 2.1, 0.8, 0.2, 0.2, 1.1, 2.3, 6.1, 8.4},
		{7.2, 9.9, 8.4, 3.3, 1.2, 0.8, 0.4, 0.0, 0.6, 1.7, 4.3, 6.2},
		{7.6, 5.6, 3.8, 2.8, 3.8, 0.2, 0.0, 0.0, 0.0, 1.3, 2.6, 5.2}
	};
	int year, month;
	float subtot, total;
	/*
	// declare a fitting pointer
	const float (* prain)[MONTHS];
	// assign this pointer-to-float[MONTHS]
	prain = rain;
	// rain or prain, both work as both are pointer-to-float[MONTHS]
	printf("%f\n", *(*(prain + 1) + 1));
	*/
	
	printf(" YEAR    RAINFALL  (inches)\n");
	for (year = 0, total = 0; year < YEARS; year++)
	{
		// for each year, sum rainfall to each month
		for (month = 0, subtot = 0; month < MONTHS; month++)
			subtot += *(*(rain + year) + month);
		printf("%5d %15.1f\n", 2000 + year, subtot);
		// total for all years
		total += subtot;
	}
	printf("\nThe yearly average is %.1f inches.\n\n",
	       total / YEARS);
	printf("MONTHLY AVERAGES:\n\n");
	printf(" Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec\n");
	
	for (month = 0; month < MONTHS; month++)
	{
		// for each month, sum rainfall over years
		for (year = 0, subtot = 0; year < YEARS; year++)
			subtot += *(*(rain + year) + month);
		printf("%4.1f ", subtot/YEARS);
	}
	printf("\n");
	
	return 0;
}