Question

PLEASE HELP DEBUG THE FOLLOWING JAVA PROGRAM

// Program displays some facts about a string
public class DebugSeven3
{
   public static void main(String[] args)
   {
      String quote =
        "Honesty is the first chapter in the book of wisdom. - Thomas Jefferson";

      System.out.println("index.of('f') is: " + indexOf('f'));
      System.out.println("index.of('x') is: " + indexOf('x'));
      System.out.println("char.At(5) is: " + charAt(5));
      System.out.println("endsWith(\"daughter\") is: " + quote.endswith("daughter"));
      System.out.println("endsWith(\"son\") is: " + quote.endswith("son"));
      System.out.println("replace('e', '*') is: " + quote.replace('e', 'M'));
   }
}

Answer 1

The are 5 compilation and 4 logical errors in the code.

The compilation errors that are generated by the code are as follows:

These errors are generated due to the syntactical errors in the code.

There are 3 logical errors in the code as well. Each of the statements contain a logical error:

System.out.println("index.of('f') is: " + indexOf('f'));

System.out.println("index.of('x') is: " +indexOf('x'));

System.out.println("charAt(5) is: " +charAt(5));

System.out.println("replace('e', '*') is: " + quote.replace('e', 'M'));

The explanation of each error and their corresponding corrections are as follows:

1.

The following statement contains a logical as well as a syntactical error:

System.out.println("index.of('f') is: " + indexOf('f'));

Explanation:

Syntactical error:

The method, indexOf(), is a method of the String class and must be called by an object of the String class. Since, there is no method defined in the scope of the program that has the name indexOf(), the program throws an error.

Logical Error:

There is also a logical error in the statement. The statement that is printed onto the console is index.of(‘f’) which states as if the method of() is being called by the variable index.

Correction:

Use the String object defined in the program to call the method indexOf().

Correct the logical error by removing the ‘.’ in between the "" and capitalizing the o in the statement.

Since, the only string defined in the program is quote, the corrected statement is therefore as follows:

System.out.println("indexof('f') is: " + quote.indexOf('f'));

2.

The following statement contains a logical as well as a syntactical error:

System.out.println("index.of('x') is: " +indexOf('x'));

Explanation:

• The method, indexOf(), is a method of the String class and must be called by an object of the String class. Since, there is no method defined in the scope of the program that has the name indexOf(), the program throws an error.
• There is also a logical error in the statement. The statement that is printed onto the console is index.of(‘f’) which states as if the method of() is being called by the variable index.

Correction:

Use the String object defined in the program to call the method indexOf(). Since, the only string defined in the program is quote, the corrected statement is therefore as follows:

Correct the logical error by removing the ‘.’ in between the "" and capitalizing the o in the statement.

System.out.println("indexOf('x') is: " + quote.indexOf('x'));

3.

Error:

The following statement contains a logical as well as a syntactical error:

System.out.println("char.At(5) is: " + charAt(5))

Explanation:

• The method, charAt(), is a method of the String class and must be called by an object of the String class. Since, there is no method defined in the scope of the program that has the name charAt (), the program throws an error.
• There is also a logical error in the statement. The statement that is printed onto the console is char.At(‘f’) which states as if the method At() is being called by the variable/type char.

Correction:

Use the String object defined in the program to call the method indexOf(). Since, the only string defined in the program is quote, the corrected statement is therefore as follows:

Correct the logical error by removing the ‘.’ in between the "" and capitalizing the a in the statement.

System.out.println("charAt(5) is: " + quote.charAt(5));

4.

Error:

The following statement contains a syntactical error:

System.out.println("endsWith(\"daughter\") is: " + quote.endswith("daughter"));

Explanation:

There is no method named endswith in the string class. The correct name of the method is endsWith().

Correction:

Correct the name of the method to obtain the following the statement:

System.out.println("endsWith(\"daughter\") is: " + quote.endsWith("daughter"));

5.

Error:

The following statement contains a syntactical error:

System.out.println("endsWith(\"son\") is: " + quote.endswith("son"));

Explanation:

There is no method named endswith in the string class. The correct name of the method is endsWith().

Correction:

Correct the name of the method to obtain the following the statement:

System.out.println("endsWith(\"son\") is: " + quote.endsWith("son"));

6.

The following statement contains a logical error:

System.out.println("replace('e', '*') is: " + quote.replace('e', 'M'));

Error:

• There is a logical error in the statement.
• The print statement indicates that the character ‘e ‘is being replaced by the character ‘*’, but the call to method replace is replacing the character e with the character M.

Correction:

Correct the statement by correcting the call to the replace method. The correct statement is therefore as follows:

System.out.println("replace('e', '*') is: " + quote.replace('e', '*'));

The corrected code is therefore as follows:

Code Screenshots:

Sample Output:

Code to Copy:

// Program displays some facts about a string

public class DebugSeven3

{

   public static void main(String[] args)

   {

      String quote =

        "Honesty is the first chapter in the book of wisdom. - Thomas Jefferson";

      System.out.println("indexof('f') is: " + quote.indexOf('f'));

      System.out.println("indexOf('x') is: " + quote.indexOf('x'));

      System.out.println("charAt(5) is: " + quote.charAt(5));

      System.out.println("endsWith(\"daughter\") is: " + quote.endsWith("daughter"));

      System.out.println("endsWith(\"son\") is: " + quote.endsWith("son"));

      System.out.println("replace('e', '*') is: " + quote.replace('e', '*'));

   }

}