
Concept explainers
Write a fragment of code that will read words from the keyboard until the word done is entered. For each word except done, report whether its first character is equal to its last character. For the required loop, use a
- a. while statement
- b. do-while statement

Explanation of Solution
a.
Using “while” statement:
The code fragment to read words until the user enters “done”. For every word, the program should check whether the first and last characters are match or not. The program using “while” condition is as follows. Code fragment is highlighted.
//Import required package
import java.util.Scanner;
//Define the Main class
public class Main
{
//Define main method
public static void main(String[] args)
{
//Create an object for scanner class
Scanner sc = new Scanner(System.in);
//Declare a variable
String word = " ";
//Do till the user enters "done"
while(!word.equals("done"))
{
//Get a word from the user
System.out.print("\nEnter a word: ");
word = sc.next();
//Check if word is equal to "done"
if(word.equals("done"))
//Break the loop
break;
//Check if 1st and last characters are equal
if(word.charAt(0) == word.charAt(word.length()-1))
//Print the message
System.out.println("The first and last character matches in '"+ word + "'");
//Else
else
//Print the message
System.out.println("The first and last character does not matches in '"+ word + "'");
}
}
}
Explanation:
- The statements under the condition “while(!word.equals("done"))” gets executed till the user enters “done”.
- The program then gets a word from the user and then it checks whether the 1st and last characters are match or not.
- The program gets halted if the user enters “done”.
Output:
Enter a word: abi
The first and last character does not matches in 'abi'
Enter a word: aruna
The first and last character matches in 'aruna'
Enter a word: done

Explanation of Solution
b.
Using “do-while” statement:
The code fragment to read words until the user enters “done”. For every word, the program should check whether the first and last character are match or not. The program using “do-while” condition is as follows. Code fragment is highlighted.
//Import required package
import java.util.Scanner;
//Define the Main class
public class Main
{
//Define main method
public static void main(String[] args)
{
//Create an object for scanner class
Scanner sc = new Scanner(System.in);
//Declare a variable
String word = " ";
//Do till the user enters "done"
do
{
//Get a word from the user
System.out.print("\nEnter a word: ");
word = sc.next();
//Check if word is equal to "done"
if(word.equals("done"))
//Break the loop
break;
//Check if 1st and last characters are equal
if(word.charAt(0) == word.charAt(word.length()-1))
//Print the message
System.out.println("The first and last character matches in '"+ word + "'");
//Else
else
//Print the message
System.out.println("The first and last character does not matches in '"+ word + "'");
} while(!word.equals("done"));
}
}
Explanation:
- The statements inside “do-while” condition gets executed till the user enters “done”.
- The program then gets a word from the user and then it checks whether the 1st and last characters are match or not.
- The program gets halted if the user enters “done”.
Output:
Enter a word: charles
The first and last character does not matches in 'charles'
Enter a word: david
The first and last character matches in 'david'
Enter a word: done
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