package test5;

import java.util.List;

public class Test5F 
{
    /**
     * Returns the number of a's in the given string.
     * 
     * @param word a string
     * @pre. word != null
     * @return the number of a's in the given string.
     */
    public static int numberOfAs(String word)
    {
	int number;
	if (word.length() == 0)
	{
	    number = 0;
	}
	else
	{
	    number = word.charAt(0) == 'a' ? 1 : 0;
	    number += Test5F.numberOfAs(word.substring(1));
	}
	return number;
    }
    
    /**
     * Tests whether all strings of the given list have the same
     * length.
     * 
     * @param sentence a list of strings
     * @pre. sentence != null
     * @return true if all strings of the given list have the same
     * length, false otherwise.
     */
    public static boolean sameLength(List<String> sentence)
    {
	boolean same;
	if (sentence.size() <= 1)
	{
	    same = true;
	}
	else
	{
	    same = sentence.get(0).length() == sentence.get(1).length()
	        && Test5F.sameLength(sentence.subList(1, sentence.size()));
	}
	return same;
    }
}