/* count_char - count the number of alphabetic characters in an input file */
/*    and print a text histogram of the counts.                            */
/*                                                                         */
/* After compiling, use the program to count the characters of a text file */
/* as follows.  Suppose you want to count the characters in proj1.c:       */
/*                                                                         */
/*                ./a.out < proj1.c                                        */

#include <stdio.h>

#define ALPHALEN 26

void histogram( int[], int, char[] );

int main() {

  /* (1) Create an integer array named 'letters' of length ALPHALEN.       */
  /*     'letters' will be used to hold the counts of each letter.         */

  /* (2) Create a character array named 'labels' of length ALPHALEN.       */
  /*     'labels' will hold character labels for the histogram.            */

  int numletters;          /* counts number of letters in input */
  char c;                 
  int i;

  /* Initialize numletters, letters, and labels */
 
  numletters = 0;

  /* (3) Use a for loop to initialize the elements of 'letters' to zero.    */
  /*     You should use the ALPHALEN constant in the test part of the loop. */


  /* (4) User a for loop to initialize the elements of 'labels' to the      */
  /*     characters 'A', 'B', ..., 'Z'.                                     */

  /* Loop over characters in input and count occurrences of each letter     */
  /* Note: counts for upper and lower case are merged                       */

  while ( (c = getchar()) != EOF ) {

    numletters++;

    if ( c >= 'a' && c <= 'z' ) {          /* if c is lowercase a..z  */

      letters[ c - 'a']++;

    } else if (c >= 'A' && c <= 'Z') {     /* if c is uppercase A..Z  */

      /* (5) The two lines before this else-if block test whether c is a    */
      /*     lowercase letter and, if so, increments the appropriate count. */
      /*     This block tests whether c is an uppercase letter.  Write a    */
      /*     statement to incrment the correct element of the 'letters'     */
      /*     array.  Hint: it is almost the same as the line                */
      /*                    letters[ c - 'a']++;                            */

    } else {                               /* otherwise c is not a letter */

      numletters--;

    }

  }

  /* Generate the histogram */

  histogram(letters, ALPHALEN, labels);
 
  return 0;
}

/* histogram() - produce a text histogram of the data in counts[] using */
/*    labels from the labels[] array.  Both counts[] and labels[] must  */
/*    have length len.                                                  */

void histogram(int counts[], int len, char labels[]) {
  int i, j;

  for (i=0; i<len; i++) {             /* loop over counts              */

    /* (6) Add a line to print the correct label at the beginning of   */
    /*     each histogram row.  The first row should have label        */
    /*     labels[0], the second label[1], etc.                        */

    for (j=0; j<counts[i]; j++) {     /* print counts[i] asterisks '*' */
      printf("*");
    }

    printf("\n");                     /* print newline at end of row   */

  }
  return;
}