/*
 * functions for use with programs that count alphabetic characters
 */
#ifndef ALPHACOUNTERS_H /* just in case we forget and #include this twice */
#define ALPHACOUNTERS_H

#include <stdio.h>
#include <stdbool.h>

/*
 * struct to hold character and count
 */
typedef struct {
	char letter;
	long count;
} letter_count_t;

/* 
 * function to build array of counter structs, with one entry for each 
 * character c for which islower(c) is true.
 *
 * sets *sz to the number of entries needed, and returns pointer to 
 * array or NULL if space for it could not be obtained using malloc().
 */
letter_count_t * build_alphacounters(int *sz);

/*
 * function to print characters in array of counter structs, all on one
 * line.
 */
void print_alphabet(FILE * f, letter_count_t counters[], int num_counters);

/*
 * function to update one element of an array of counters built by
 * build_alphacounters.
 * 
 * parameter ch gives the (lowercase) character for which the counter
 * should be incremented.
 * 
 * parameter incr says how much to increment it.
 *
 * parameters counters and counters_sz give the array of counters and
 * its size.
 */
bool update_counter(char ch, int incr,
		letter_count_t counters[], int num_counters);

#endif