Question

PLEASE HELP! Need to understand for upcoming test :(

Recursion sure is tough

Write a recursive method (not a complete program) that is passed a string. Your method should return the Boolean constant true if the string has NO occurrences of the letter "A". otherwise should return false

Answer 1

// Recursive function to check occurrence of character 'A' in the passed string str
public static boolean count(String str) {
    // if str length is greater than 1 and 'A' is present at first position return true
    if (str.length() >= 1 && str.charAt(0) == 'A')
        return true;
    else {
        // if str length is greater than 1 then call count method recursively on substring of str
        if (str.length() > 1)
            return count(str.substring(1));
        else
            return false;
    }
}

// Output

The non-occurence of 'A' in string BCC is true The non-occurence of 'A' in string BCA is false Process finished with exit code 0