Question

I am having some trouble writing some java code involving strings. I have included the code provided by my professor below. that has the instructions in it as well

public class StringExercise {
  public static void main(String[] args) {
    String given = "The quick brown fox jumped over the moon!";
    
    String given2 = "mary";
    
    String given3 = "D";
    
    
    //Write a Java code snippet to check (print a boolean) whether the given String ends with the contents of "oon!", see endsWith method
    
    //Write a Java code snippet to check (print a boolean) whether the given String starts with the contents of "Th", see startsWith method
    
    //Write a Java code snippet to check (print a boolean) whether the given2 String has the same contents as the String "mark", see equals method
    
    //Write a Java code snippet to check (print a boolean) whether the given2 String has the same contents, ignoring case, as the String "MARY", see equalsIgnoreCase method
    
    //Write a Java code snippet to print all the indices where the letter 'o' is located at in the given String. See indexOf method and use a while loop.
    
    //Write a Java code snippet to print the substring of the given String from indices 3 through 8. See substring method.
    
    
    //Write a Java code snippet to compare the given3 String with the String "Z" using the compareTo method. Print the integer that is
    //returned from the compareTo method.
    
    
    //Write a Java code snippet to compare the given3 String with the String "A" using the compareTo method. Print the integer that is
    //returned from the compareTo method.
    
    
    //Write a Java code snippet to compare the given3 String with the String "D" using the compareTo method. Print the integer that is
    //returned from the compareTo method.
    
  }

}

Answer 1

Code:

public class StringExercise {

    public static void main(String[] args) {

        String given = "The quick brown fox jumped over the moon!";
  String given2 = "mary";
  String given3 = "D";

        // Write a Java code snippet to check (print a boolean) whether the given String

        // ends with the contents of "oon!", see endsWith method

        System.out.println(given.endsWith("oon!"));

        // Write a Java code snippet to check (print a boolean) whether the given String

        // starts with the contents of "Th", see startsWith method

        System.out.println(given.startsWith("Th"));

        // Write a Java code snippet to check (print a boolean) whether the given2

        // String has the same contents as the String "mark", see equals method

        System.out.println(given2.equals("mark"));

        // Write a Java code snippet to check (print a boolean) whether the given2

        // String has the same contents, ignoring case, as the String "MARY", see

        // equalsIgnoreCase method

        System.out.println(given2.equalsIgnoreCase("MARY"));

        // Write a Java code snippet to print all the indices where the letter 'o' is

        // located at in the given String. See indexOf method and use a while loop.

        int index = given.indexOf('o');

        while (index >= 0) {

            System.out.println(index);

            index = given.indexOf('o', index + 1);

        }

// we get the first index of 'o' and then iterate to find the next occurences in the remaining string.
// .indexOf('o',index) begins the search from index, so the previous one is not counted.

        // Write a Java code snippet to print the substring of the given String from

        // indices 3 through 8. See substring method.

        System.out.println(given.substring(3, 9));

  //9 is exculsive. So, to get the substring from 3 to 8, we pass 3 and 9 as parameters.

        // Write a Java code snippet to compare the given3 String with the String "Z"

        // using the compareTo method. Print the integer that is

        // returned from the compareTo method.

        System.out.println(given3.compareTo("Z"));

        // Write a Java code snippet to compare the given3 String with the String "A"

        // using the compareTo method. Print the integer that is

        // returned from the compareTo method.

        System.out.println(given3.compareTo("A"));

        // Write a Java code snippet to compare the given3 String with the String "D"

        // using the compareTo method. Print the integer that is

        // returned from the compareTo method.

        System.out.println(given3.compareTo("D"));

    }

}

Reference screenshot:

Output of the code:

Explanation:

The string object in java comes with many predefined functions to perform operations on strings. In this exercise you are being asked to use some of them.

• stringVariable.endsWith("parameterString") -- checks if our string ends with the specified string.
• stringVariable.startsWith("parameterString") -- checks if our string starts with the specified string.
• stringVariable.equals("parameterString") -- compares the string charater by charater to find if they are equal or not
• stringVariable.equalsIgnoreCase("parameterString") -- compares the string charater by charater to find if they are equal or not while ignoring the case of characters whether upper or lower.
• stringVariable.indexOf("string/character") -- returns the first index in the string of character passed as parameter.
• stringVariable.indexOf("string/character", int index) -- returns the first index in the string of character passed as parameter. It starts the search after the input index.
• stringVariable.substring(beginIndex, endIndex) -- returns the part of whole string specified by the indices given in parameter. The endIndex is exclusive, meaning substring(3,8) returns the string from index 3 to 7.
• stringVariable.compareTo("parameterString") -- Compares the strings lexicographically. The result is a negative integer if this String object lexicographically precedes the argument string. The result is a positive integer if this String object lexicographically follows the argument string. The result is zero if the strings are equal.