Check if a String Contains Only Alphabets in Java using ASCII Values

// Java Program to Check if a String Contains Only Alphabets
// Using ASCII values

// Importing required classes
import java.util.*;

// Class 1
// Main class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating object of helper class
        Helper h = new Helper();

        // Print statement
        System.out.println(
            h.isStringOnlyAlphabet("geeksforgeeks"));
    }
}

// Class 2
// Helper class
class Helper {

    public static boolean isStringOnlyAlphabet(String str)
    {

        // If string is empty or null
        if (str == null || str.equals("")) {

            // Return false
            return false;
        }

        // If we reach here we have character/s in string
        for (int i = 0; i < str.length(); i++) {

            // Getting character at indices
            // using charAt() method
            char ch = str.charAt(i);
            if ((!(ch >= 'A' && ch <= 'Z'))
                && (!(ch >= 'a' && ch <= 'z'))) {
                return false;
            }
        }

        // String is only alphabetic
        return true;
    }
}

// Java program to check if String contains only Alphabets
// Using ASCII Values

// Main class
class GFG {

    // Method 1
    // To check String for only Alphabets
    public static boolean isStringOnlyAlphabet(String str)
    {

        // If there is no string
        if (str == null || str.equals("")) {
            return false;
        }

        // Iterating as now we encounter string
        // using length() method
        for (int i = 0; i < str.length(); i++) {

            char ch = str.charAt(i);

            // Checking for any other aphabetic character
            // present in string
            if ((!(ch >= 'A' && ch <= 'Z'))
                && (!(ch >= 'a' && ch <= 'z'))) {

                // Then string is not only alphabetic
                return false;
            }
        }

        // If we reach here, it means
        // string is only aphabetic
        return true;
    }

    // Method 2
    // Main method
    public static void main(String[] args)
    {

        // Checking for True case
        System.out.println("Test Case 1:");

        String str1 = "GeeksforGeeks";
        System.out.println("Input: " + str1);
        System.out.println("Output: "
                           + isStringOnlyAlphabet(str1));

        // Checking for String with numeric characters
        System.out.println("\nTest Case 2:");

        String str2 = "Geeks4Geeks";
        System.out.println("Input: " + str2);
        System.out.println("Output: "
                           + isStringOnlyAlphabet(str2));

        // Checking for null String
        System.out.println("\nTest Case 3:");

        String str3 = null;
        System.out.println("Input: " + str3);
        System.out.println("Output: "
                           + isStringOnlyAlphabet(str3));

        // Checking for empty String
        System.out.println("\nTest Case 4:");

        String str4 = "";
        System.out.println("Input: " + str4);
        System.out.println("Output: "
                           + isStringOnlyAlphabet(str4));
    }
}