Trail: Learning the Java Language
Lesson: Numbers and Strings
Questions and Exercises
Home Page > Learning the Java Language > Numbers and Strings

Questions and Exercises: Characters and Strings

Questions

  1. What is the initial capacity of the following string builder?

    StringBuilder sb = new StringBuilder("Able was I ere I saw Elba.");
    
  2. Consider the following string:

    String hannah = "Did Hannah see bees? Hannah did.";
    
    1. What is the value displayed by the expression hannah.length()?

    2. What is the value returned by the method call hannah.charAt(12)?

    3. Write an expression that refers to the letter b in the string referred to by hannah.

  3. How long is the string returned by the following expression? What is the string?

    "Was it a car or a cat I saw?".substring(9, 12)
    
  4. In the following program, called ComputeResult, what is the value of result after each numbered line executes?

    public class ComputeResult {
        public static void main(String[] args) {
            String original = "software";
            StringBuilder result = new StringBuilder("hi");
            int index = original.indexOf('a');
    
    /*1*/   result.setCharAt(0, original.charAt(0));
    /*2*/   result.setCharAt(1, original.charAt(original.length()-1));
    /*3*/   result.insert(1, original.charAt(4));
    /*4*/   result.append(original.substring(1,4));
    /*5*/   result.insert(3, (original.substring(index, index+2) + " ")); 
    
            System.out.println(result);
        }
    }
    

Exercises

  1. Show two ways to concatenate the following two strings together to get the string "Hi, mom.":

    String hi = "Hi, ";
    String mom = "mom.";
    
  2. Write a program that computes your initials from your full name and displays them.

  3. An anagram is a word or a phrase made by transposing the letters of another word or phrase; for example, "parliament" is an anagram of "partial men," and "software" is an anagram of "swear oft." Write a program that figures out whether one string is an anagram of another string. The program should ignore white space and punctuation.

Check your answers.


Problems with the examples? Try Compiling and Running the Examples: FAQs.
Complaints? Compliments? Suggestions? Give us your feedback.

Previous page: Autoboxing and Unboxing
Next page: Generics (Updated)



Spec-Zone.ru - all specs in one place