STRING CONCATENATION USING JAVA LANGUAGE

Q-13- Assume a string variable ruler1 contains “1” initially i.e.     String   ruler1=”1” Write a java program to print the following output using string concatenation. (You can take extra string variables)

             1
             1 2 1
             1 2 1 3 1 2 1
             1 2 1 3 1 2 1 4 1 2 1 3 1 2 1

INPUT :
public class NCM {

public static void main(String[] args) {
// TODO Auto-generated method stub
String ruler1="1";
System.out.println(ruler1);
System.out.println(ruler1+" 2 "+ruler1);
ruler1=ruler1+" 2 "+ruler1;
System.out.println(ruler1+" 3 "+ruler1);
ruler1=ruler1+" 3 "+ruler1;
System.out.println(ruler1+" 4 "+ruler1);
}


}

OUTPUT :
1
1 2 1
1 2 1 3 1 2 1

1 2 1 3 1 2 1 4 1 2 1 3 1 2 1