Lesson2.java

package test;

public class Lesson2 {

	public static void main(String[] args) {
		System.out.println(getFirstCharacterOfWord(null,2));
		System.out.println(getFirstCharacterOfWord("   ",2));
		System.out.println(getFirstCharacterOfWord("ahjkji",1));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",0));
		System.out.println(getFirstCharacterOfWord("df  jdbj cbfhd   efhfbwh  wehbfh khbdsh dcbhb",5));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",2));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",3));
		System.out.println(getFirstCharacterOfWord("df jdbj   cbfhd efhfbwh     wehbfh          khbdsh dcbhb",4));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",5));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",6));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",7));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd    efhfbwh    wehbfh khbdsh    dcbhb",8));
		System.out.println(getFirstCharacterOfWord("df jdbj cbfhd efhfbwh wehbfh khbdsh dcbhb",20));
	}
	
	static char getFirstCharacterOfWord(String str,int numberWord)
	{
		//proverka na sushestvovanie stroki
		if(str==null || str=="")
		{
			System.out.println("String is not found");
			return 0;
		}
		//proverka na nomer slova>0
		if(numberWord<1)
		{
			System.out.println("Index not correct");
			return 0;
		}
		//proverka na nomer slova > kolichestva slov v stroke 

		int index=0,k=1;
		
		while(str.lastIndexOf(" ")>index)
		{
			index=str.indexOf((" "), index)+1;
			
			if(str.charAt(index)!=' ')//kolichestvo slov uvelichetsya,esli posle probela ne stoit snova probel
			   k++;
		}
		if(k<numberWord)
		{
		    System.out.println("Index > number of words");
		    return 0;
		}
	
		index=0;k=1;
		
	    while(true)
		{
			if(numberWord==k)
				return str.charAt(index);
			
			index=str.indexOf(" ",index);
			
		//Proverka esli stroka tolko iz probelov ili bolshe odnogo probela megdu slovami	
			
			while(str.charAt(index)==' ')
			{
			  if(index+1==str.length())
			  {
				  System.out.println("String have not any word");
				  return 0;
			  }
			  index++;
			}
			
			k++;
		}
		
	}
	
	}