// LettersCounter.c : Questo file contiene la funzione 'main', in cui inizia e termina l'esecuzione del programma.
//
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAX_W_LEN 20
#define NUM_LETTERS 26
#define MIN_LEN 8

int counter(char* filewords, int* alphabet)
{
	FILE* fp;
	char a[MAX_W_LEN+1];
	if ((fp = fopen(filewords, "r")) == NULL)
	{
		printf("Error opening file %s: %s\n", filewords, strerror(errno));
		return(1);
	}
	memset(a, '\0', sizeof(a));
	while (fscanf(fp, "%s", a) != EOF)
	{
		if (strlen(a) >= MIN_LEN)
		{
			//printf("%s\n", a);
			for (int i = 0; i < strlen(a); ++i)
			{
				if (a[i] >= 'a' && a[i] <= 'z')
					++alphabet[a[i] - 'a'];
			}
		}
		memset(a, '\0', sizeof(a));
	}
	return(0);
}

int main(int argc, char* argv[])
{
	int alphabet[NUM_LETTERS];

	if (argc != 2)
	{
		printf("Error: usage %s filename_to_read", argv[0]);
		exit(1);
	}
	printf("Filename to be read: %s\n", argv[1]);

	for (int i = 0; i < NUM_LETTERS; i++)
	{
		alphabet[i] = 0;
	}

	if (counter(argv[1], alphabet) == 0)
	{
		for (int i = 'a'; i <= 'z'; ++i)
		{
			if (alphabet[i - 'a'] > 0)
			{
				//printf("There are %d occurrences of the character %c\n", alphabet[i - 'a'], i);
				printf("<%c:%d>\t", i, alphabet[i - 'a']);
			}
		}
	}
	exit(0);
}