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

Questions and Exercises: Characters and Strings


  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) + " ")); 


  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.

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