Question

Purpose: Once you have completed and tested the functionality of your MyStringBuilder class, you will do a rough comparative test to see how long some of the operations take relative to the predefined StringBuilder class and the predefined String class.

Details: You will complete a simple simulation to compare the times required for three operations: append(char c) , insert(int loc, char c) and delete(int start, int stop) These methods are defined in the StringBuilder and MyStringBuilder classes, but you will have to approximate them with the String class, since it is immutable [part of the assignment is to figure out how to approximate these with a String - as a hint look at the substring() method in the String class].

You will test these operations in the following way:

- Write a program called Assig2B.java, which will be the main program for the rest of this description.

- Your main program will be invoked with a command line argument, which is the number of characters that you will be appending / inserting into your string objects. Call this value N. Since the value of the character does not matter here, you can just use all character 'A's for your operations.

- In your main program, you will iterate 3 times, once for each of the three test classes (StringBuilder, MyStringBuilder and String). For each iteration in your main program, you will do the following:

- Create a new object of the class that is being tested

- Time the operations as described below. For more details on the procedure for timing, see below.

- Time append(): Use the append() method (or String approximation thereof) to add each of the N characters to the end of the current testing object.

- Time delete(0,1): Remove the first character of the current testing object repeatedly until the object contains no more characters (a total of N characters should be removed).

- Time insert(): Process the N characters again. However, this time you will insert() each character into the middle of the testing object. The "middle" of the object can be determined by dividing the length by 2. Be careful to test for special cases!

- For each of your Time operations above you should proceed in the following way:

- Mark the start "time" of your test with a call to System.nanoTime() - Perform ALL of the operations on the current testing object (i.e. append / insert all N characters into or remove all N characters from the object)

- Mark the stop "time" of your test with a call to System.nanoTime()

- Calculate the elapsed time for all of the operations by subtracting the start time from the stop time

- Calculate the average time per operation by dividing the elapsed time by the number of characters processed (either appended / inserted or deleted)

- Output your results to the display, both for the total time and the time per operation

Run your program with each of the following input values for N: 10000, 20000, 40000, 80000, 160000

Answer 1

Qo.

ANS:

Java program to append a string using StringBuilder

JAVA Code:

/** USING StringBuilder append */
import java.lang.*;
import java.util.*;
public class Assig2B{
   public static void main(String args[])
   {   
       int choice;
       System.out.println("********* LEGENDS ****************");
       System.out.println("Enter 1 for Appending");
       System.out.println("Enter 2 for Inserting");
       System.out.println("Enter 3 for Deleting");
       System.out.println("1. APPEND(N) \n2. INSERT(pos,char) \n3. DELETE (startPosition, endPostion)");
       Scanner ch=new Scanner(System.in);
       System.out.print("What Do You Want? Enter Your Choice: ");
       choice=ch.nextInt();
       switch(choice)
       {
           //Append n chars long string
           case 1: String userStr;
                   int n;
                   Scanner s = new Scanner(System.in);
                   System.out.println("Intial String:");
                   StringBuilder SBinput = new StringBuilder("I Like Chegg India "); //Let's consider this is initial string
                   System.out.println(SBinput);
                   System.out.print("How Many Character(s) You want to append? ");
                   n=s.nextInt();
                   Scanner iptstr = new Scanner(System.in);
                   System.out.print("Enter "+n+" Charcter Long String : ");
                   userStr = iptstr.nextLine();
                   String snipName = userStr.substring(0, n); //automatically snip string when you'll enter the string greater than limit
                   if (userStr.length()>n)
                   {
                       userStr=snipName;
                   }
                   System.out.print("You've entered: " +userStr);
                   System.out.println();
                   //Appending Operation of n char long string
                   SBinput.append(userStr);
                   System.out.println("After Appending: ");
                   System.out.println(SBinput);
                   break;
                  
           //inserting a string at desired position
           case 2: char ins;
                   int pos;
                   Scanner ob=new Scanner(System.in);
                   StringBuilder initStr = new StringBuilder("I Like Chegg India ");
                   System.out.println("Intial String = " + initStr);
                   System.out.print("Which charcter you want to insert? Enter that: ");
                   ins=ob.next().charAt(0);
                   System.out.print("On Which Position You want to Insert? ");
                   pos=ob.nextInt();
          
                   //insert char at offset value on the user given position
                   initStr.insert(pos,ins);

                   // prints StringBuilder after insertion
                   System.out.print("After insertion = ");
                   System.out.println(initStr.toString());
                   break;
                  
           //DELETION a string from start position to end position
           case 3: int startPos, endPos;
                   StringBuilder str = new StringBuilder("I Like Chegg India ");
                   System.out.println("Intial String = " + str);
                   Scanner obj=new Scanner(System.in);
                  
                   System.out.println(" DELETING A STRING ");
                   System.out.println("Enter Start Position: ");
                   startPos=obj.nextInt();
                   System.out.println("Enter End Position: ");
                   endPos=obj.nextInt();
                   //deleting chars from start index to end index
                   str.delete(startPos, endPos);
                   System.out.println("After deletion = "+str);
                   break;
                  
           default: System.out.println("Your Choice is Wrong!!");
       }
   }
}

OUTPUT IMAGE1:

APPEND OPERATION

Administrator: C:Windows System32 cmd.exe C:Users \hp Desktop java new?>javac Assig2B.java C:\Users\hp\Desktop\JavaNnew7)Java Assig2B Enter 1 for Appending Enter 2 for Inserting Enter 3 for Deleting APPENDN 2. INSERT(pos,char〉 3. DELETE <startPosition, endPostion> What Do You Want? Enter Your Choice: 1 Intial String: I Like Chegg India How Many Character(s You want to append? 9 Enter 9 Charcter Long String Questions You'e entered: Questions After Appending: I Like Chegg India Questions C:AUsers hp Desktop java\new?>_

OUTPUT IMAGE2:

INSERT OPERATION

C:\Users\hp\Desktop.javaNnew?〉javac Assig2B.java C:\Users\hp\Desktop\Java\new?〉java Assig2B Enter 1 for Appending Enter 2 for Inserting Enter 3 for Deleting 1. APPEND N 2. INSERT <pos,char> DELETE sta t Position, endPostion〉 What Do You Want? Enter Your Choice: 2 Intial String = 1 Like Chegg India Which charcter you want to insert? Enter that: s On Which Position You want to Insert? 6 After insertionI Likes Chegg India

OUTPUT IMAGE3:

DELETE OPERATION

C:\Users\hp\Desktop\Java\n eu?〉Java Assig2B Enter 1 for Appending Enter 2 for Inserting Enter 3 for Deleting 1. APPEND〈N> 2. INSERT (pos char> 3. DELETE <startPosition, endPostion> What Do You Want? Enter Your Choice: 3 Intial StringILike Chegg India DELETING A STRING Start Position: Enter End Position: 13 After deletion India C:XUsers hp Desktop.iava new?>

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THANKS!!