//
// example of recursion:
//   function to count alphabetic characters in string, plus test program
//
#include <iostream.h>
#include <stdlib.h>		// has EXIT_SUCCESS
#include <iomanip.h>		// has setw() 
#include <ctype.h>		// has isalpha()

// Function to count alphabetic characters in string.
// Pre:  s contains a null-terminated string and n <= strlen(s)
// Post:  returns the number of alphabetic characters in s,
//        starting with s[n]
int countAlpha(const int n, const char s[])
{
  if (s[n] == '\0')
    return 0;
  else if (isalpha(s[n]))
    return 1 + countAlpha(n+1, s);
  else
    return countAlpha(n+1, s);
}

// Main program.
int main(void)
{
  const int BUFFSIZE = 1000;
  char instring[BUFFSIZE];

  cout << "Enter a character string:\n";
  // setw() guards against overrunning end of "instring" array.
  cin >> setw(BUFFSIZE) >> instring;

  cout << '"' << instring << '"' << " contains " 
       << countAlpha(0, instring) << " alphabetic characters\n";

  return EXIT_SUCCESS;
}