Java Menu Driven Program to Check Character Type

In this article, we will see a menu driven program to check if the entered character is number, string or special character by Java programming language. We will be implementing the application using a switch case.

To show you some instances 

Instance-1

Suppose the entered character is ?a' then the output should be "Entered character is a String".

Instance-2

Suppose the entered character is ?1' then the output should be "Entered character is a number".

Instance-3

Suppose the entered character is ?$' then the output should be "Entered character is a Special character".

Syntax

To check whether a character is String, Number or a Special character in Java we use isLetter, isDigit or isWhitespace functions. String is checked by isLetter function, Number is checked by isDigit function and special character is checked by combination of isLetter, isDigit and isWhitespace function.

Following is the syntax for String function

Character.isLetter(ob1)

Following is the syntax for number function

Character.isDigit(ob1)

Following is the syntax for String function

(!Character.isDigit(ob1)&& !Character.isLetter(ob1)&& !Character.isWhitespace(ob1))

Algorithm

Step-1 ? Ask the user to input the desired character.

Step-2 ? Display the menu.

Step-3 ? Ask the user to enter their choice.

Step-4 ? Use a switch case to go to the choice and perform the operation.

Step-5 ? Print the result.

Let's see the program to understand it clearly.

Example

import java.util.*;
public class Main {
   public static void main(String args[]) {
      Scanner sc = new Scanner( System.in );
      System.out.println("Enter a character to check if it's a Number, String or a Special character");
      char ob1 = sc.next().charAt(0);

      System.out.println("Now choose the operation you want to perform from the menu given below. ");

      mainLoop: while (true) {
         Scanner inn = new Scanner( System.in );
         System.out.println("\n***Menu***");
         System.out.println("1. Check if a character is number");
         System.out.println("2. Check if a character is String");
         System.out.println("3. Check if a character is Special character");
         System.out.println("4. Terminate the program");
         System.out.println("Enter action number (1-4): ");
         int command;
         if ( inn.hasNextInt() ) {
            command = inn.nextInt();
            inn.nextLine();
         }
         else {
            System.out.println("\nILLEGAL RESPONSE. YOU MUST ENTER A NUMBER.");
            inn.nextLine();
            continue;
         }
         switch(command) {
            case 1:
            if (Character.isDigit(ob1)) {
               System.out.println("Character is a number!");
            } else {
               System.out.println("Character is not a number!");
            }
            break;
            case 2:
            if (Character.isLetter(ob1)) {
               System.out.println("Character is a String!");
            } else {
               System.out.println("Character is not a String!");
            }
            break;
            case 3:
            if (!Character.isDigit(ob1)
            && !Character.isLetter(ob1)
            && !Character.isWhitespace(ob1)) {
               System.out.println("Character is a Special Character!");
            } else {
               System.out.println("Character is not a Special Character!");
            }
            break;
            case 4:
            System.out.println("Program terminated");
            break mainLoop;
            default:
            System.out.println("Wrong choice!!");
         }

      }

   }
}

Output

Enter a character to check if it's a Number, String or a Special character
t
Now choose the operation you want to perform from the menu given below.
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
1
Character is not a number!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
3
Character is not a Special Character!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
2
Character is a String!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
$
ILLEGAL RESPONSE. YOU MUST ENTER A NUMBER.
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
1
Character is not a number!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
3
Character is not a Special Character!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
2
Character is a String!
***Menu***
1. Check if a character is number
2. Check if a character is String
3. Check if a character is Special character
4. Terminate the program
Enter action number (1-4):
4
Program terminated

In this article, we explored how to check if a character is a string, number or special character in Java by using a menu driven approach.