//
// Program:  count_space.
//
// Purpose:  test recursive function to count spaces in character
//   string.
//
// Input:
//   a line of text from standard input.
// Output:
//   the number of whitespace characters in the input text, printed
//   to standard output.
#include <iostream.h>
#include <stdlib.h>
#include <ctype.h>

// Pre: s contains a null-terminated string; n >= 0 and < length(s).
// Post:  returns number of whitespace characters in s, starting
//          from position n.
int count_space(char s[], int n)
{
  if (s[n] == '\0')
    return 0;
  else if (isspace(s[n]))
    return 1 + count_space(s, n+1);
  else
    return count_space(s, n+1);
}

// Main program.

int main(void)
{
  const int N = 200;
  char line[N];
  cout << "Enter a line of text:\n";
  cin.getline(line, N);
  cout << "That line contains " << count_space(line, 0) 
       << " whitespace characters.\n";
  return EXIT_SUCCESS;
}