Answer:
import java.util.Scanner;
public class num3 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter Favorite color");
        String word1 = in.next();
        System.out.println("Enter Pet's name");
        String word2 = in.next();
        System.out.println("Enter a number");
        int num = in.nextInt();
        //Point One
        System.out.println("You entered: "+word1+" "+word2+
                " "+num);
        //Point Two
        String passwordOne = word1+"_"+word2;
        String passwordTwo = num+word1+num;
        System.out.println("First password: "+passwordOne);
        System.out.println("Second password: "+passwordTwo);
        //Point Three
        int len_passwrdOne = passwordOne.length();
        int len_passwrdTwo = passwordTwo.length();
        System.out.println("Number of characters in "+passwordOne+" :" +
                " "+len_passwrdOne);
        System.out.println("Number of characters in "+passwordTwo+" :" +
                " "+len_passwrdTwo);
    }
}
Explanation:
- This question is solved using java programming language
- The scanner class is used to receive the three variables (Two string and one integer)
- Once the values have been received and stored in the respective variables (word1, word2 and num), Use different string concatenation to get the desired output as required by the question.
- String concatenation in Java is acheived with the plus (+) operator.