public class Test
{	public static void main(String[] args)
	{	
		//1.ַ
		String greeting1="Hello";
		String greeting2="World";
		String greeting= greeting1+greeting2;
		System.out.println(greeting);
		//2.Ӵ
		String s=greeting1.substring(0,4);
		System.out.println(s);
		//3.ַĳ
		int n=greeting1.length();
		System.out.println(n);
		//4.ַǷ
		String greeting3="Hello";
		String greeting4="hello";
		boolean b1=greeting1.equals(greeting3);
		boolean b2=greeting1.equals(greeting4);
		boolean b3=greeting1.equalsIgnoreCase (greeting3);
		boolean b4=greeting1.equalsIgnoreCase (greeting4);
		System.out.println("b1="+b1);
		System.out.println("b2="+b2);
		System.out.println("b3="+b3);
		System.out.println("b4="+b4);
		//5.Сдת
		String uppergreeting=greeting1.toUpperCase();
		String lowergreeting=greeting1.toLowerCase();
		System.out.println(uppergreeting);
		System.out.println(lowergreeting);
	}
}
