Question

Assignment Purpose

Write a well commented java program that demonstrates the use and re-use of methods with input validation.

Instructions

1. It is quite interesting that most of us are likely to be able to read and comprehend words, even if the alphabets of these words are scrambled (two of them) given the fact that the first and last alphabets remain the same. For example,

“I dn'ot gvie a dman for a man taht can olny sepll a wrod one way.” (Mrak Taiwn)

“We aer all moratls, Hamrbee is an immoratl, and tehre is no question abuot it.” (Kevin Unknown)

2. Write a method named scramble that returns a String and takes a String as an argument.
   1. The argument is actually a word (of length 6 or more).
   2. It then constructs a scrambled version of that word, randomly flipping two characters other than the first and last one.
3. Then write the main method in which you would read the word from the user, send it to scramble, and print the scrambled word.
   1. You can use a loop to read multiple words if you like but it is not necessary.
   2. If the length of the entered word is less than 6, you should keep prompting the user to enter a valid word.
4. After writing all the comments, generate a Javadoc and submit it with the java file.

Hint: First generate two random integers in range of the length of the string. Then use substring method to access characters at those locations. Rest is left to your imagination.

Submission

A .java and a .html (generated with Javadoc) file

Answer 1

import java.util.Random;
import java.util.Scanner;

public class A {
        /**
        * Returns a scramble string. 
        * The string argument is the string which user wants to scramble. 
        * <p>

        * @param       str string to be scrambled
        * @return      the scrambled string
        */
        public static String scramble(String str)
        {
                Random rand=new Random();
                int n=str.length();
                int r;
                StringBuilder s=new StringBuilder(str);
                for(int i=1;i<n-1;i++)
                {
                        r=Math.abs(rand.nextInt(n-2))+1;
                        s.setCharAt(i, str.charAt(r));
                        s.setCharAt(r, str.charAt(i));
                        str=s.toString();
                }
                return s.toString();
        }
        public static void main(String[] args) {
                // TODO Auto-generated method stub
                Scanner src=new Scanner(System.in);
                System.out.println("Enter any string:");
                String s=src.next();
                while(s.length()<6)
                {
                        System.out.println("Enter a valid word");
                        s=src.next();
                }
                System.out.println(scramble(s));

        }

}