A clean solution to Exercise 1-12

[ChenZhongPu]

#include <stdbool.h>
#include <stdio.h>

int main() {
  int c;
  bool in_word = false;

  while ((c = getchar()) != EOF) {
    if (c == ' ' || c == '\t' || c == '\n') {
      if (in_word) {
        putchar('\n');
      }
      in_word = false;
    } else {
      putchar(c);
      in_word = true;
    }
  }
  return 0;
}