src/kr_exercises/ch1/s1.6/e1-13..histogram_word_length.c

   1 #include <stdio.h>
   2
   3 /* Exercise 1-13. Write a program to print a histogram of the length
   4    of words in its input. It is easy to draw the histogram with the
   5    bars horizontal; a vertical orientation is more challenging. */
   6
   7 #define MAX_LEN      4  /* Max acceptable word length */
   8 #define MAX_DISP_LEN 70  /* Max length of horizontal bar */
   9 #define IN            1  /* Inside a word */
  10 #define OUT           0  /* Outside a word */
  11
  12 int main() {
  13   int n, c, i, j, state, nwchar;
  14   int wlen[ MAX_LEN + 1 ];
  15
  16   state = OUT;
  17   nwchar = n = 0;
  18   for (int i = 0; i <= MAX_LEN; ++i)
  19     wlen[i] = 0;
  20
  21   /* Populate wlen[] */
  22   while ( (c = getchar()) != EOF ) {
  23     n++;  /* Track loop number. */
  24     /* Check if whitespace */
  25     if ( c == ' ' || c == '\n' || c == '\t' ) {
  26       /* printf("%d:DEBUG:In whitespace.\n", n); */
  27       /* I'm in whitespace */
  28       /* Check if I just departed a word */
  29       if ( state == IN ) {
  30         /* Increment appropriate element of wlen[] */
  31         if ( nwchar <= MAX_LEN )
  32           ++wlen[nwchar];
  33         else
  34           ++wlen[0]; /* Use zero-index for words longer than MAX_LEN */
  35       };
  36       /* Remember I'm not in a word */
  37       state = OUT;
  38       nwchar = 0;
  39     } else {
  40       /* printf("%d:DEBUG:In word.\n", n); */
  41       /* I'm in a word. */
  42       /* Check if I just departed whitespace*/
  43       if ( state == OUT ) {
  44         /* I just started a word. */
  45         nwchar = 1;
  46       } else {
  47         /* I'm in a word. */
  48         ++nwchar;
  49       }
  50
  51       /* Remember I'm in a word. */
  52       state = IN;
  53     }
  54
  55     /* End of while loop stats */
  56     /* printf("%d:DEBUG:nwchar:%d\n", n, nwchar);    */
  57   }
  58
  59
  60   /* /\* DEBUG:display wlen[] *\/ */
  61   /* printf("wlen[]:");   */
  62   /* for (i = 0; i < MAX_LEN; ++i) */
  63   /*   printf(" %d", wlen[i]); */
  64   /* printf("\n"); */
  65
  66   /* int tn = 0; */
  67   /* ++tn; */
  68   /* printf("wlen[%d]:%d\n", tn, wlen[tn]); */
  69
  70
  71   /* Display wlen[] contents */
  72   /* Iterate through elements of wlen[] (skipping zeroth element) */
  73   for (i = 1; i <= MAX_LEN; ++i) {
  74     /* Print bar for i'th entry in wlen[] */
  75     printf("%d: ", i);
  76     for (j = 0; j < wlen[i]; ++j ) {
  77       if ( j < MAX_DISP_LEN )
  78         printf("#");
  79     }
  80
  81     printf("\n");
  82   };
  83
  84   /* Print bar for 0'th entry in wlen[] (words exceeding MAX_LEN) */
  85   printf("%d+: ", MAX_LEN + 1 );
  86   for (j = 0; j < wlen[0]; ++j )
  87     if ( j < MAX_DISP_LEN )
  88       printf("#");
  89   printf("\n");
  90
  91   return 0;
  92 };
  93
  94 /* Author: Steven Baltakatei Sandoval
  95    License: GPLv3+ */