Question

Write a JAVAprogram that reads a word and prints all its substrings, sorted by length. It then generates a random index between 0 and the length of the entered word, and prints out the character at that index.

For example, if the user provides the input "rum", the program prints
r
u
m
ru
um
rum

The random index generated is 1. The character at index 2 is u.

Answer 1

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

public class Main
{
   public static void main(String[] args)
   {
   //variable declaration
   String s;
   int n, randNum;
       Scanner sc = new Scanner(System.in);
       //display message
        System.out.print("Enter a string: ");
        //input string
        s = sc.nextLine();
        //calculate the length of the input string
        n = s.length();
       
        //generate random number
        Random rand = new Random();
randNum = rand.nextInt(n);
       
        //display message
        System.out.println("The substring are: ");
       
        //generate all substring
        for (int len = 1; len <= n; len++)
        {
for (int i = 0; i <= n - len; i++)
{
int j = i + len - 1;
for (int k = i; k <= j; k++)
{
System.out.print(s.substring(k, k+1));
}
  
System.out.println();
}
}
//display character at random position
System.out.println("\nThe random number generated is " + randNum + ". The character at index " + randNum + " is " + s.charAt(randNum-1));
   }
}

OUTPUT: