Write a Java program that prompts the user for a string. If the string entered by the user does not start with Hello and does not end with a digit, print incorrect and re-prompt the user. Otherwise, print Thank you.
import java.util.Scanner;
public class ReviewQuestion4 {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.print(“Enter string: “);
String input = keyboard.nextLine();
while (input.length() < 5 ||
!input.substring(0,5).equals(“Hello”) ||
!Character.isDigit(input.charAt(input.length()-1))) {
System.out.println(“Incorrect.”);
System.out.print(“Enter string: “);
input = keyboard.nextLine();
}
System.out.println(“Thank you!”);
}
}
To write a Java program that prompts the user for a string, checks if it starts with "Hello" and ends with a digit, and prints the appropriate message, you can follow these steps:
1. Create a new Java class and define the main method.
2. Inside the main method, create a Scanner object to read user input from the console.
3. Prompt the user to enter a string using the System.out.println statement. For example:
```java
System.out.println("Enter a string: ");
```
4. Use the Scanner's nextLine() method to read the user's input and store it in a String variable. For example:
```java
String input = scanner.nextLine();
```
5. Use the String class methods to check if the input starts with "Hello" and ends with a digit. You can use the `startsWith()` method to check the starting part, and the `matches()` method with a regular expression to check the ending with a digit. For example:
```java
boolean isValid = input.startsWith("Hello") && input.matches(".*\\d$");
```
6. If the input is not valid, print "Incorrect" using the System.out.println statement and re-prompt the user. You can use a loop to repeatedly prompt the user until a valid input is given. For example:
```java
while (!isValid) {
System.out.println("Incorrect. Please enter the string again: ");
input = scanner.nextLine();
isValid = input.startsWith("Hello") && input.matches(".*\\d$");
}
```
7. Once a valid input is entered, print "Thank you" using the System.out.println statement. For example:
```java
System.out.println("Thank you!");
```
8. Finally, close the Scanner object to release system resources. Use the scanner.close() method. For example:
```java
scanner.close();
```
Here's the complete Java program:
```java
import java.util.Scanner;
public class StringValidationProgram {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
boolean isValid = false;
while (!isValid) {
System.out.println("Enter a string: ");
String input = scanner.nextLine();
isValid = input.startsWith("Hello") && input.matches(".*\\d$");
if (!isValid) {
System.out.println("Incorrect. Please enter the string again: ");
}
}
System.out.println("Thank you!");
scanner.close();
}
}
```
This program will keep prompting the user for a string until a valid input is entered, according to the provided conditions.