histogram.c

/* Exercise 1-13. Write a program to print a histogram of the lengths
of words in its input. */

/*
  input = (special | word)*
  special = blank | tab | newline
  word = non-special+
 */

#include<stdio.h>
#define N 64

int
main(int argc, char argv[]) {
  int ch;
  int wordlen;
  int b[N];
  int i,j,last;
  char buf[N];
  
  for (i=0; i<N; i++) {
    b[i] = 0;
  }
  
  ch = getchar();
  while (ch != EOF) {
    switch (ch) {
    case ' ':
    case '\t':
    case '\n':
      ch = getchar();
      break;
    default:
      wordlen = 0;
      for (i=0; i<N; i++) {
	buf[i] = 0;
      }
      i = 0;
      while (ch != EOF && ch != ' ' && ch != '\t' && ch != '\n') {
	wordlen++;
	buf[i++] = ch;
	ch = getchar();
      }
      b[wordlen]++;
      buf[i] = 0;
    }
  }
  
  /* find the last non-zero entry */
  last = N-1;
  while (last>=0 && b[last]==0) {
    last--;
  }
  
  /* print histogram without scaling */
  for (i=1; i<last+1; i++) {
    for (j=0; j<b[i]; j++) {
      putchar('*');
    }
  putchar('\n');
  }

  return 0;
}