ITSC 1213 Lab 3 Purpose: To read and use the Java API documentation for the Stri

Question

ITSC 1213 Lab 3 Purpose: To read and use the Java API documentation for the String class and the StringBuilder class. Step 1. Step 1 is done on paper, not with BlueJ. Open the Java 8 API documentation and answer the following questions about the String class methods. String state = new String (“Mississippi”); String captitalCity = new String (“Jackson”); String university = new String(“Old Miss”); Using the above String object references, look at the Java API documentation and state which method(s) you would use to accomplish the following tasks: get the first letter of state. find out if state contains the substring “pi” create a new String that contains only the “Miss” from the String state. create a new String that has as its data: “Jackson, Mississippi” find out which has more characters in it: state or capitalCity create a new String with all the ‘i’s in “Mississippi changed to ‘o’s. create a new String from university, that holds the data: “OLD MISS” determine if capitalCity ends with the letters: “sen” or “son” determine if state and university contain the same letters, regardless of case. Find the positions of all the letter ‘s’s in the String state. This will take more than one Java statement. What is the difference in use/purpose between the String class and the StringBuilder class? List five methods of the StringBuilder class. Step 2. Write all of this code in main( ) in a test class. Write a main( ) method that declares a String reference variable. Read a sentence (with spaces) using keyboard input. Create a String object using this input. Input a sentence that is long enough and has enough letters to accomplish each of the following tasks. Write the String method calls and print the output for each of these tasks. Note that some of these cannot be written with one line of code and one String class method call. Print the number of characters your sentence contains. Print the first letter of your sentence Print the last letter of your sentence Print whether your sentence contains the letter ‘e’ Print whether your sentence contains “ay” or not. Print the number of times the letter ‘e’ appears in your sentence Find the position of the last occurrence of the letter ‘e’ in your sentence Find the position of the second occurrence of the letter ‘e in your sentence Print how many characters your sentence contains besides the space character. Add the words “you know” to the sentence Print a completely upper case version of your sentence Extract and print a substring of five characters from your sentence Print a String where all the chars ‘a’ are replaced with the char ‘x’ Step 3: Write a project to perform manipulations on a string of characters. Write a program that will allow the user to change every occurrence of the space character with the string, “blank”. Create two classes. Replacer class, which has at least two fields, the original string, stored in a String object and the converted string, stored in a StringBuilder object. The constructor method should take a String as a parameter and assign it to both fields. You need a replace( ) method that will take in two parameters, the character to be replaced and the sequence of characters to replace it with. This method will use StringBuilder methods and logic to change all occurrences of the original string to a new string, while still preserving a copy of the original string. Write a get( ) method to get the original string. Write a get( ) method to get the converted string. Write a set( ) method to change the original string to a new string provided by the user. Driver class: Write a class with the main( ) method that tests your Replacer class. The user can enter strings, and convert each to another string using the replace( ) method that you wrote. Use the get( ) methods to print results to the screen. Allow the user to enter a brand new string until they decide they are done.

Explanation / Answer

/*declaration of variables where the data are passing in constructor*/

String state=new String("Mississipi"); // state is an object

String capitalCity= new String("Jackson"); //capitalCity is an object

String university=new String("Old Miss"); // university is an object

/* Question 1.Method to find out the first letter of the state

we use substring() method for this. the syntax is public String substring(int beginIndex, int lastIndex)

as here we are trying to findout the first letter only.The syntax will be substring(0,1)

the code snippet will be-----*/

String state1=state.substring(0,1);

System.out.println(state1);

// output: M

/*Question 2 find out if state contains the substring “pi”*/

String state2=state.substring(8,10);

Syso(state2);

/*Question 3 create a new String that contains only the “Miss” from the String state.*/

String state3=state.subString(0,4);

Syso(state3);

/*Question4 create a new String that has as its data: “Jackson, Mississippi” */

//this can be done using concat method.The general syntax is public String concat(String str)

String state4=state.concat(",").concat(capitalCity);

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