whitespace filter

#include <iostream>
#include <stdio.h>
using namespace std;

int main() {
  char ch1, ch2;

  cin.get(ch1);
  for (;;) {
    if (cin.fail()) break;
    if (ch1 == '\n') cout << ch1;
    if(ch1 == ' ' || ch1 == '\t' || ch1 == '\n') {
      cin.get(ch1);
      continue;
    } else {
      cout << ch1;
      cin.get(ch2);
      if (ch2 == '\t') ch2 = ' ';
    }

    for (;;) {
      ch1 = ch2;
      cin.get(ch2);
      if (ch2 == '\t') ch2 = ' ';
      if (ch1 == ' ' && ch2 == ' ') {
        continue;
      }
      else if (ch1 == ' ' && ch2 == '\n') {
        cout << ch2;
        break;
      } else if (ch1 == '\n') {
        cout << ch1;
        ch1 = ch2;
        break;
      } else {
        cout << ch1;
      }
    }
  }
}