1-13

Quest: page 24

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• Write a program to print a histogram of the length of the words in its input. It is easy to draw the histogram with the bars horizontal. a vertical orientation is more challenging.

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• step 1 generate testdata for the program
  note

  i generated a file with containing each word 3 times with a length from 1 to 99

generate testfile

#include <stdio.h>
#include <stdlib.h>

#define MAX 100

int main() {

  FILE *f = fopen("txt", "w");
  if (f == NULL) {
    return EXIT_FAILURE;
  }
  for (int i = 1; i < MAX; i++) {
    for (int k = 0; k < 3; k++) {
      for (int j = 0; j < i; j++) {
        fprintf(f, "w");
      }
      fprintf(f, " ");
    }
    fprintf(f, "\n");
  }
  fclose(f);
  return EXIT_SUCCESS;
}

• step 2 print the histogram
  note

  My assumption is that each word is no longer than 1000 characters.

histogram program

#include <stdio.h>
#include <stdlib.h>

#define MAX 1000

int main() {
  int c;
  int wl = 0;
  int vi[MAX] = {0};

  while ((c = getchar()) != EOF) {
    // lets assume there are only three seperators
    if (c == ' ' || c == '\t' || c == '\n') {
      // note here we check if the current wl fits into the array
      if (wl <= MAX && wl > 0) {
        vi[wl]++;
      }
      wl = 0;
    } else {
      wl++;
    }
  }
  for (int i = 0; i < MAX; i++) {
    if (vi[i] > 0) {
      printf("wordlength %d: %d times\n", i, vi[i]);
    }
  }
}