// countLetters.cpp
// Counts the number of letters in a string.
// Uses a while loop.

#include <iostream>
using namespace std;

int main()
{
   const int LENGTH = 15;

   // Announce purpose of program:
   cout << "Enter a string without white space, up to "
           << LENGTH << " characters.";
   cout << "This program will tell you how many letters "
             << "the string contains." << endl;

   // Ask user for a string, and echo it:
   cout << "Enter your string:>";
   char text[LENGTH + 1];
   cin >> text;
   cout << "You typed: " << text << endl;

   // No letters have been found YET:
   int countLetters = 0;

   // Count letters:
   int index = 0;   // Start at the beginning of the string.
   while ( text[index] != '\0')    // until end of string
   {
      // If the character at index is a letter, add one
      // to count of letters.  Then, whether or not the
      // character is a letter, prepare to look at the
      // next character.

      if ( (text[index] >= 'A'  &&  text[index] <= 'Z')
              ||  (text[index] >= 'a'  &&  text[index] <= 'z') )
         countLetters = countLetters + 1;

      index = index + 1;
   }  // while

   // Output result:
   cout << "Your string contains " << countLetters
            << " letters." << endl;

   return 0;
}  // function main