Searching Array - Read From A File That Is List Of Songs
Oct 10, 2014
I have an assignment for my intro class that requires me to read from a file that is a list of songs, their artists, and the year they were released. As seen below, a print line statement prompts the user to enter an artist name, and then it uses a buffered reader to gain input, and then it is supposed to match that input.I realize that this is not a complete statement, but I'm mostly concerned with getting the .indexOf statement to work.Currently it only returns the first object in the array.
for(int i = 0; i < song.length; i++) {
System.out.println("Enter an Artist name");
String input1 = kb.readLine();
if (song[i].getArtist().indexOf(input1) > -1) {
/*tried changing -1 to -2. When I do, it returns the
first array entry, regardless of what I input*/
System.out.println(song[i].toString());
}
}
An array which contain a list of names. I let for a user input and I use that to search through the array. For example lets say the string name "Christian" is stored inside the names array and the user types in Chri, the program looks in the array and finds a name that contains Chri and prints them out. How do I go about doing this?
I am creating a hangman game and I want to read in a list of words from a text file, but after the user inputs the name of the text file. I get 'Exception in thread "main" java.lang.NullPointerException'.
Here is the code, where I think the problems lie.
public void runModel(){ ArrayList<String> pirateWordsList = new ArrayList<String>(); System.out.println("What is the name of the file you would like to load? (The file included is called piratewords.txt'"); Scanner in=new Scanner(System.in); String file=in.next(); load(file);
[Code] ....
The full error message is this:
Exception in thread "main" java.lang.NullPointerException at uk.ac.aber.dcs.pirate_hangman.Model.load(Model.jav a:108) at uk.ac.aber.dcs.pirate_hangman.Model.runModel(Model .java:45) at uk.ac.aber.dcs.pirate_hangman.Main.main(Main.java: 6)
Ok here I have a code that generates 1 million random values then converts them to a string then hashcode. I then insert into a linked list and then I want to run through each hash and find it in the linked list timing each run then averaging out the time at the end.
It works great for smaller amounts of numbers it is searching for (fine under 50 thousand searches for the for loop starting at line 24 LinkedListTest.java) but when I try to do the full million searches it gives me "a Exception in thread "main" java.lang.StackOverflowError" at line 158 in List.java. Maybe im getting tired but I cannot figure out why.
// class to represent one node in a list class ListNode< T > { // package access members; List can access these directly T data; // data for this node ListNode< T > nextNode; // reference to the next node in the list
So I need to be able to find the longest increasing sequence in a 2D grid of numbers. A sequence is simply a series of adjacent squares. Squares may not be used twice. Example here.
The longest sequence has length 10, consisting of entries (row, column) as follows;
(5,0) with cost 12 (6,0) with cost 14 (6,1) with cost 15 (6,2) with cost 20 (7,2) with cost 44 (7,3) with cost 52 (7,4) with cost 54 (6,3) with cost 71 (5,3) with cost 74 (4,3) with cost 96
I wouldn't be having a problem if I could use a 2D Array but the assignment requires the use of a List and StringTokenizer.
The way it works, a file is read and each row of the grid is an element of the List of Strings. So in the example above if I were to call myList.get(1) it would return 35 57 41 13 82 80 71 93 31 62 since it's the second row and second index value of the List.
If it was a 2D array I would check values at [x-1][x-1],[x-1][x]... to check all sides and diagonals ect ect. But with the List and Tokenizer there isn't a way that I know of that can search through the String using index values.
I wouldn't even know where to start with that. As of now I read the file fine and make the List of Strings and populate it properly, I'm just a little stuck. I should also mention that which ever method I use to search needs to be recursive.
This is what little I have. It reads in the file, creates the list and assigns the rows to the list.
import java.util.*; import java.io.*; public class MaxIncreasingSub { public static void main(String []args) throws Exception{ File file = new File("Ass1Q2_test1"); List<String> myList = new ArrayList<String>();
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product { public String pName; public String stringName; public double price; public int quanity;
[Code] .....
And then here is the data from the text file that i must extract to use to create product objects.
These continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quantity after the second comma.....
New to programming. Am supposed to create a program that reads a text file (of integers) and computes a series of computations on these integers. I don't have the code for the integers in my code yet, (i know how to do those), but am struggling getting the array to simply print in the print writer. I have the user select a text file, read the file with a scanner, and then save the computations done from my code into another file. specifically, the problem is as follows: Write a program that uses a file chooser dialog to select a file containing some integers. The file contains an integer N followed by N integers. The program then uses a file chooser dialog to let the user specify the name and location of an output file to write results to.The data written to the output file will be as follows
(1) The original list of N numbers from the input file, (2) The original list of N numbers printed in reverse order of how they appear in the input file. (3) The sum and average of these numbers, (4) The minimum of all the numbers, (5) The maximum of all the numbers.
I am trying to read a file and input each line of the file into an array. I have not set the array size as I was hoping to fill the array using a while loop. Unfortunately the scope of the array does to work inside the while loop so I am being told that the array 'students' has not been initialised even though it has just outside of the while loop. Is it possible to do what I am trying to without having the array initialised in the while loop as surely the array will be reset every time if it was in the while loop? Here is my code:
public static void students(String file) throws FileNotFoundException { try { File studentInfo = new File(file); Scanner input = new Scanner(studentInfo); String[] students;
with arrays its binary search which finds a value in O(Logn) time but what about linked lists ? the most effiecient algorithm will be O(n) ? and i know that binary search cannot be implement on a linked list , therefore , the only way to search a linked list is a linear search ?
I have to write a program for sorting an array of random numbers by the users choice. These random numbers are stored in a text file, which the user inputs, and is then stored into an array for sorting. I won't have a problem with the sorting algorithms, but I've never had to read a text file and store it into an array before
The text file has the numbers stored like so : 148 626 817 4 312 652 643 etc....
I gather that I'll probably have to user the Scanner for the user to input the text file name, but how do I store it to an array? So far I only have the bones of the program done, like so
import java.util.Scanner; public class SortingAlgorithms { public static void main(String[] args) {
I am trying to read in lines of text from a file then prints out the text. I only need one 2D array and can't copy from one array to another.This how the file looks like:
4 4 FILE WITH SOME INFO
I have been able to read the file but when I am trying to run my program I have blank spacing instead of an array.
import java.util.Scanner; import java.io.*; public class Array { public static void main(String[] args) throws IOException{
I am trying to read numeric values from a text file into an array. This is what i have so far but when i compile it, it doesn't run and give me a result.
import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.PrintWriter; import java.util.Scanner; public class question2_17110538 {
I'm trying to figure out the necessary code for reading integers from a text file, then placing them withing the two-dimensional array I have created, and then finally printing the array using a nested for-loop. I have attached the file I would like to read from. I'm having trouble figuring out how to reference the text file with the integers, and also how to properly create a dynamic preface for each row of the array. I want the preface to display as "Week #: ", with # being the row number. I tried to create an integer to be used that way, but NetBeans tells me whatever integer I declare has already been defined in method main. I know I need to use scanner to read the file. I would like the output to display like this:
I'm supposed to write a program, which reads float numbers from a file, puts them in an array and sorts the array. After that I'm suppose to add the numbers so that when I add the 1 and 2 number of the array, I'm suppose to save the sum on the position of number 1, then I add number 3 and 4 and save the sum on position 2 etc. Also if my array has an uneven number of floats it's suppose to add the last 3 and not 2 numbers in the last iteration. The problem is the method throws an ArrayOutOfBounds Exception but I can't seem to find my mistake.
That's the second method. The first one just stores the sum in another variable and then returns it. Also is there a way in that I can Scanner/File/array etc. and initialize the array only once so I don't write the same code two times like it is now.
package sumOfFloats;
import java.io.File; import java.io.FileNotFoundException; import java.util.Arrays; import java.util.Scanner; public class SumOfFloats { public static float sumFloats() throws FileNotFoundException{
The point of this program is to read characters from a txt file and store them into a 2D array. After this has been accomplished, the information is to be printed in the same manner it is read from in the txt file.
Here is the code I have so far:
import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class Main { public static void main(String[] args) throws FileNotFoundException
[Code] ....
And this is the error I am receiving when trying to accomplish the goal of the project:
Exception in thread "main" java.lang.NumberFormatException: For input string: "############" at java.lang.NumberFormatException.forInputString(Unk nown Source) at java.lang.Integer.parseInt(Unknown Source) at java.lang.Integer.parseInt(Unknown Source) at Maze.<init>(Maze.java:15) at Main.main(Main.java:20)
What's going on here and how I can correct this?? The information I am trying to store in a 2D array and then print is this:
The main method will drive your program by doing the following:
-Create an array to hold all the individual golfers and par scores (type is Golfer[ ]). -Prompt the user for a data file containing the Par scores and the player names and score. The format of the input file should look like
I am learning about arrays in my class and my professor has a habit of throwing in code without explaining. We are doing a program called storing largest numbers where we read data from a file and place the larger of the two numbers in the corresponding position of a third array. They are in 4 by 4 format. Here is the ending code
import java.io.*; import java.util.*; public class prog464aStoringLargestNums { public static void main(String[] args)
I'm trying to read from a file. we made an array of LinkedList and when I'm reading from the file i get a runtime error "index out of bounce in line 66"
import java.lang.*; import java.util.*; public class HashTester{ LinkedList_t [] hash; LinkedList_t [][] doubleHasher; int size;
If I specify the directory in file type or path string type how can I get a list of files that are file type .yml in that folder, so I can loop through and do something with each single file.yml in that specified directory.
'm working on a program that is to act as an inventory for a book store. There are two classes (Store and Book), and numerous methods which you will see in my code. The program is supposed to read in an inventory from a file which contains 10 books (each row in the file represents a book with an ISBN number, the price of the book, and the number in stock)and store this file into an array of type Book[]. There is then to be another method to process a purchase interactively. The Store class is also to keep a count of how many books were sold at the time of closing and also how much was made that day.
I'm having some difficulty figuring out how I should set up the purchase processing method though. I've written out how I think it would be set up (not too familiar with the terminology, but I think it would be called pseudo code?) I'll include that now along with a few other notes.
public Book[] purchase(String isbn, double price, int copies) { int itemsSold; double totalMade; Scanner input = new Scanner(System.in); System.out.println("Please enter the ISBN number of the book you would like to purchase: ");
[Code] ....
So basically here's what needs to be accomplished with this portion of code:
1.Ask the user to enter the ISBN number of the book they'd like to purchase. 2.Search the array for the object that contains that ISBN. 3.If the ISBN isn't found in the array, display a message stating that we don't have that book. 4.If the ISBN is found but the number of copies is 0, display a message saying the book is out of stock. 5.If the ISBN is found and the number of copies is greater than 0, ask the user how many copies they'd like to purchase. 6.If the number they enter is greater than the number of copies of that book in the array, display a message stating that and ask them to enter another quantity. 7.Once the purchase is complete I need to update the array by subtracting the number of copies of that particular book that was purchased. 8.Print the updated array. 9.Display a count of how many books were purchased, and how much money was made from the purchase.
I know that code has a lot of holes in it, but I'm just trying to get everything together and figure out how to do each step.
The part I'm stuck on right now is trying to figure out how to search the array to first see if the ISBN that was entered is in the array, and then to find the number of copies of the book with that ISBN number.
In case it will visualize what this array looks like, here's a print out of the array from a sample run I just did.
An array which contain a list of names. I let for a user input and I use that to search through the array. For example lets say the string name "Christian" is stored inside the names array and the user types in Chri, the program looks in the array and finds a name that contains Chri and prints them out. How do I go about doing this?
