import  java.io.*;
import java.util.StringTokenizer;

class StringOp { 										//read the task2 class name

    public static void main(String args[ ]) throws IOException

    {

        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));	//read the string
        System.out.println("Enter the string: ");

        String s=br.readLine();
        StringTokenizer st=new StringTokenizer(s);

        System.out.println("1.Convert sentence to uppercase");			//giving possibilities
        System.out.println("2.Convert sentence to lowercase");
        System.out.println("3.Display each word in the sentence");
        System.out.println("4.Search for a word in the sentence");
        System.out.println("5.Replace space with $ symbol in the sentence");
        System.out.println("6.Quit the Program");


        System.out.println("Enter your choice:");				//choice reading

        int x=Integer.parseInt(br.readLine());

        switch(x){

            case 1:
                System.out.println(s.toUpperCase());				//converting to uppercase
                break;
            case 2:
                System.out.println(s.toLowerCase());				//converting to lower case
                break;
            case 3:
                for(;st.hasMoreElements();){					//prints each token
                    System.out.println(st.nextToken());
                    //System.out.println();
                    break;
                }
            case 4:
                System.out.println("Enter sub string");				//reads substring and compares
                String ss=br.readLine();
                int intIndex = s.indexOf(ss);
                if(intIndex == - 1){
                    System.out.println("Hello not found");
                }else{
                    System.out.println("Found Hello at index "
                            + intIndex);
                }
                break;
            case 5:
                System.out.println( s=s.replace(" ", "$") );			//replace the string space with $
                break;

            case 6:
                System.exit(0);							//exit from the system

            default:
                System.out.println("tell me what to do.. i m quit");
        }
    }
}

 OUTPUT:

Enter the string: 
Programming9
1.Convert sentence to uppercase
2.Convert sentence to lowercase
3.Display each word in the sentence
4.Search for a word in the sentence
5.Replace space with $ symbol in the sentence
6.Quit the Program
Enter your choice:
1
PROGRAMMING9
 

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