ex_1-14.c

#include <stdio.h>
#include <limits.h>

int main ()
{
  int c, i, j, maxnum;
  int ndigit[CHAR_MAX] = { 0 };

  maxnum = 0;

  for (i = 0; i < 10; i++)
    ndigit[i] = 0;

  while ((c = getchar ()) != EOF)
    if (c > CHAR_MAX)
      {				/* chars outside CHAR_MAX skipped */
      }
    else
      {
	++ndigit[c];
      }

  /* print out histogram */
  for (i = 0; i <= CHAR_MAX; ++i)	// find maximim count to determine graph height
    if (ndigit[i] > maxnum)
      {
	maxnum = ndigit[i];
      }

  for (i = 0; i < maxnum; ++i)	// one row for each instance of number
    {
      printf ("\n");
      printf ("%d\t|", maxnum - i);	// print sidebar
      for (j = 0; j <= CHAR_MAX; ++j)	// one column for each number
	{
	  if (ndigit[j] > 0)	// skip chars not represented in file
          {
	    if (ndigit[j] >= maxnum - i)
	      {
		putchar ('*');
	      }
	    else
	      {
		putchar (' ');
	      }
	  }
	}
    }

  /* print vertically ascii value of char printed */
  printf ("\n\t ");
  for (i = 0; i <= CHAR_MAX; ++i)
    {
      if (ndigit[i] > 0)
	{
	  printf ("%d", i / 100);
	}
    }
  printf ("\n\t ");
  for (i = 0; i <= CHAR_MAX; ++i)
    {
      if (ndigit[i] > 0)
	{
	  printf ("%d", (i - (100 * (i / 100))) / 10);
	}
    }
  printf ("\n\t ");
  for (i = 0; i <= CHAR_MAX; ++i)
    {
      if (ndigit[i] > 0)
	{
	  printf ("%d", i - (10 * (i / 10)));
	}
    }
  printf ("\n");
  return 0;
}