Search Results

Search found 6031 results on 242 pages for 'imaginary numbers'.

Page 211/242 | < Previous Page | 207 208 209 210 211 212 213 214 215 216 217 218  | Next Page >

• How can I distribute x cakes amongst y people?

  - by Rupert

  I have an associative array with the ids of x cakes and another associative array with the ids of y people. I want to ensure that each cake is enjoyed by exactly 2 people and that each person gets a fair share of cake overall. However, cakes must be kept whole (i.e. if the average cake per person is a fraction, this fraction will be rounded up for some, and down for others). No person can be assigned the same cake twice. For example: $cake = array('id'=>'1','id'=>'2') $people = array('id'=>'1','id'=>'2','id'=>'3') In order to do so, I wish to create a new array where each row represents a cake-person assignment. As each cake is being assigned to two people, the number of rows in this table should be exactly twice the number of cakes. There will not be exactly 1 solution to this problem but a solution to the above example would be: $cake_person = array( '1'=>array('cake_id'=>'1', 'person_id'=>'1'), '2'=>array('cake_id'=>'1', 'person_id'=>'2'), '3'=>array('cake_id'=>'2', 'person_id'=>'2'), '4'=>array('cake_id'=>'2', 'person_id'=>'3'), ) Notice that people 1 and 3 are losing out but that is because there is no more cake to go around! Each cake must be given exactly twice. How can I generate such a solution reliably for larger numbers of people and cakes?

  Read the article

• Why won't this work; opencv Mat_<float>

  - by user1371674

  I can't seem to get this to work. I'm trying to get the pixel value of an image but first need to change the color of the image, but since I cannot use int or just Mat because the values are not whole numbers, I have to use and because of that errors pop up when I try to run this on the cmd. int main(int argc, char **argv) { Mat img = imread(argv[1]); ofstream myfile; Mat_<float> MatBlue = img; int rows1 = MatBlue.rows; int cols1 = MatBlue.cols; for(int x = 0; x < cols1; x++) { for(int y = 0; y < rows1; y++) { float val = MatBlue.at<cv::Vec3b>(y, x)[1]; MatBlue.at<cv::Vec3b>(y, x)[0] = val + 1; } } }

  Read the article

• Unit Testing - Algorithm or Sample based ?

  - by ohadsc

  Say I'm trying to test a simple Set class public IntSet : IEnumerable<int> { Add(int i) {...} //IEnumerable implementation... } And suppose I'm trying to test that no duplicate values can exist in the set. My first option is to insert some sample data into the set, and test for duplicates using my knowledge of the data I used, for example: //OPTION 1 void InsertDuplicateValues_OnlyOneInstancePerValueShouldBeInTheSet() { var set = new IntSet(); //3 will be added 3 times var values = new List<int> {1, 2, 3, 3, 3, 4, 5}; foreach (int i in values) set.Add(i); //I know 3 is the only candidate to appear multiple times int counter = 0; foreach (int i in set) if (i == 3) counter++; Assert.AreEqual(1, counter); } My second option is to test for my condition generically: //OPTION 2 void InsertDuplicateValues_OnlyOneInstancePerValueShouldBeInTheSet() { var set = new IntSet(); //The following could even be a list of random numbers with a duplicate var values = new List<int> { 1, 2, 3, 3, 3, 4, 5}; foreach (int i in values) set.Add(i); //I am not using my prior knowledge of the sample data //the following line would work for any data CollectionAssert.AreEquivalent(new HashSet<int>(values), set); } Of course, in this example, I conveniently have a set implementation to check against, as well as code to compare collections (CollectionAssert). But what if I didn't have either ? This is the situation when you are testing your real life custom business logic. Granted, testing for expected conditions generically covers more cases - but it becomes very similar to implementing the logic again (which is both tedious and useless - you can't use the same code to check itself!). Basically I'm asking whether my tests should look like "insert 1, 2, 3 then check something about 3" or "insert 1, 2, 3 and check for something in general" EDIT - To help me understand, please state in your answer if you prefer OPTION 1 or OPTION 2 (or neither, or that it depends on the case, etc )

  Read the article

• iPhone - sorting the results of a core data entity

  - by Digital Robot

  I have a core data entity that represents the attributes of a product, as number, price, etc. The product number is a NSString property and follows the form X.y where X is a number variable of digits and Y is one digit. For example. 132.2, 99.4, etc. I am querying the database to obtain the list of product numbers in order: The code is like this: + (NSArray*)todosOsItens:(NSString *)pName inManagedObjectContext:(NSManagedObjectContext *)context { Product *aProduct = [Product productWithName:pName inManagedObjectContext:context]; NSArray *all = nil; NSFetchRequest *request = [[NSFetchRequest alloc] init]; request.entity = [NSEntityDescription entityForName:@"Attributes" inManagedObjectContext:context]; request.predicate = [NSPredicate predicateWithFormat: @"(belongsTo == %@)", aProduct]; [request setResultType:NSDictionaryResultType]; [request setReturnsDistinctResults:YES]; [request setPropertiesToFetch:[NSArray arrayWithObject:item]]; NSSortDescriptor *sortByItem = [NSSortDescriptor sortDescriptorWithKey:@"ProductNumber" ascending:YES]; NSArray *sortDescriptors = [NSArray arrayWithObject:sortByItem]; [request setSortDescriptors:sortDescriptors]; NSError *error = nil; all = [[context executeFetchRequest:request error:&error] mutableCopy]; [request release]; return all; } but this query is not returning the sorted results. The results are coming on their natural order on the database. How do I do that? thanks.

  Read the article

• Sorted queue with dropping out elements

  - by ffriend

  I have a list of jobs and queue of workers waiting for these jobs. All the jobs are the same, but workers are different and sorted by their ability to perform the job. That is, first person can do this job best of all, second does it just a little bit worse and so on. Job is always assigned to the person with the highest skills from those who are free at that moment. When person is assigned a job, he drops out of the queue for some time. But when he is done, he gets back to his position. So, for example, at some moment in time worker queue looks like: [x, x, .83, x, .7, .63, .55, .54, .48, ...] where x's stand for missing workers and numbers show skill level of left workers. When there's a new job, it is assigned to 3rd worker as the one with highest skill of available workers. So next moment queue looks like: [x, x, x, x, .7, .63, .55, .54, .48, ...] Let's say, that at this moment worker #2 finishes his job and gets back to the list: [x, .91, x, x, .7, .63, .55, .54, .48, ...] I hope the process is completely clear now. My question is what algorithm and data structure to use to implement quick search and deletion of worker and insertion back to his position. For the moment the best approach I can see is to use Fibonacci heap that have amortized O(log n) for deleting minimal element (assigning job and deleting worker from queue) and O(1) for inserting him back, which is pretty good. But is there even better algorithm / data structure that possibly take into account the fact that elements are already sorted and only drop of the queue from time to time?

  Read the article

• LINQ - Splitting up a string with maximum length, but not chopping words apart.

  - by Stacey

  I have a simple LINQ Extension Method... public static IEnumerable<string> SplitOnLength(this string input, int length) { int index = 0; while (index < input.Length) { if (index + length < input.Length) yield return input.Substring(index, length); else yield return input.Substring(index); index += length; } } This takes a string, and it chops it up into a collection of strings that do not exceed the given length. This works well - however I'd like to go further. It chops words in half. I don't need it to understand anything complicated, I just want it to be able to chop a string off 'early' if cutting it at the length would be cutting in the middle of text (basically anything that isn't whitespace). However I suck at LINQ, so I was wondering if anyone had an idea on how to go about this. I know what I am trying to do, but I'm not sure how to approach it. So let's say I have the following text. This is a sample block of text that I would pass through the string splitter. I call this method SplitOnLength(6) I would get the following. This i s a sa mple b lock o f text that I would pass t hrough the s tring splitt er. I would rather it be smart enough to stop and look more like .. This is a sample // bad example, since the single word exceeds maximum length, but the length would be larger numbers in real scenarios, closer to 200. Can anyone help me?

  Read the article

• Strange thread behavior in Perl

  - by Zaid

  Tom Christiansen's example code (à la perlthrtut) is a recursive, threaded implementation of finding and printing all prime numbers between 3 and 1000. Below is a mildly adapted version of the script #!/usr/bin/perl # adapted from prime-pthread, courtesy of Tom Christiansen use strict; use warnings; use threads; use Thread::Queue; sub check_prime { my ($upstream,$cur_prime) = @_; my $child; my $downstream = Thread::Queue->new; while (my $num = $upstream->dequeue) { next unless ($num % $cur_prime); if ($child) { $downstream->enqueue($num); } else { $child = threads->create(\&check_prime, $downstream, $num); if ($child) { print "This is thread ",$child->tid,". Found prime: $num\n"; } else { warn "Sorry. Ran out of threads.\n"; last; } } } if ($child) { $downstream->enqueue(undef); $child->join; } } my $stream = Thread::Queue->new(3..shift,undef); check_prime($stream,2); When run on my machine (under ActiveState & Win32), the code was capable of spawning only 118 threads (last prime number found: 653) before terminating with a 'Sorry. Ran out of threads' warning. In trying to figure out why I was limited to the number of threads I could create, I replaced the use threads; line with use threads (stack_size => 1);. The resultant code happily dealt with churning out 2000+ threads. Can anyone explain this behavior?

  Read the article

• getting string.substring(N) not to choke when N > string.length

  - by aape

  I'm writing some code that takes a report from the mainframe and converts it to a spreadsheet. They can't edit the code on the MF to give me a delimited file, so I'm stuck dealing with it as fixed width. It's working okay now, but I need to get it more stable before I release it for testing. My problem is that in any given line of data, say it could have three columns of numbers, each five chars wide at positions 10, 16, and 22. If on this one particular row, there's no data for the last two cols, it won't be padded with spaces; rather, the length of the string will be only 14. So, I can't just blindly have dim s as string = someStream.readline a = s.substring(10, 5) b = s.substring(16, 5) c = s.substring(22, 5) because it'll choke when it substrings past the length of the string. I know I could test the length of the string before processing each row, and I have automated the filling of some of the vsariables using a counter and a loop, and using the counter*theWidthOfTheGivenVariable to jump around, but this project was a dog to start with (come on! turning a report into a spreadsheet?), but there are many different types of rows (it's not just a grid), and the code's getting ugly fast. I'd like this to be clean, clear, and maintainable for the poor sucker that gets this after me. If it matters, here's my code so far (it's really crufty at the moment). You can see some of my/its idiocy in the processSection#data subs So, I'm wondering 1) is there a way baked in to .NET to have string.substring not error when reading past the end of a string without wrapping it in a try...catch? and 2) would it be appropriate in this situation to write a new string class that inherits from string that has a more friendly substring function in it? ETA: Thanks for all the advice and knowledge everyone. I'll go with the extension. Hopefully one of these years, I'll get my chops up enough to pay someone back in kind. :)

  Read the article

• Listening UDP or switch to TCP in a MFC application

  - by Alexander.S

  I'm editing a legacy MFC application, and I have to add some basic network functionalities. The operating side has to receive a simple instruction (numbers 1,2,3,4...) and do something based on that. The clients wants the latency to be as fast as possible, so naturally I decided to use datagrams (UDP). But reading all sorts of resources left me bugged. I cannot listen to UDP sockets (CAsyncSocket) in MFC, it's only possible to call Receive which blocks and waits. Blocking the UI isn't really a smart. So I guess I could use some threading technique, but since I'm not all that experienced with MFC how should that be implemented? The other part of the question is should I do this, or revert to TCP, considering reliability and implementation issues. I know that UDP is unreliable, but just how unreliable is it really? I read that it is up to 50% faster, which is a lot for me. References I used: http://msdn.microsoft.com/en-us/library/09dd1ycd(v=vs.80).aspx

  Read the article

• Attempted GCF app for Android

  - by Aaron

  I am new to Android and am trying to create a very basic app that calculates and displays the GCF of two numbers entered by the user. Here is a copy of my GCF.java: package com.example.GCF; import java.util.Arrays; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class GCF extends Activity { private TextView mAnswer; private EditText mA, mB; private Button ok; private String A, B; private int iA, iB; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mA = (EditText) findViewById(R.id.entry); mB = (EditText) findViewById(R.id.entry1); ok = (Button) findViewById(R.id.ok); mAnswer = (TextView) findViewById(R.id.answer1); ok.setOnClickListener(new OnClickListener() { public void onClick(View v) { A = mA.getText().toString(); B = mB.getText().toString(); } }); // the String to int conversion happens here iA = Integer.parseInt(A.trim()); iB = Integer.parseInt(B.trim()); while (iA != iB) { int[] nums={ iA, iB, Math.abs(iA-iB) }; Arrays.sort(nums); iA=nums[0]; iB=nums[1]; } updateDisplay(); } private void updateDisplay() { mAnswer.setText( new StringBuilder().append(iA)); } } Any Suggestions? Thank you!

  Read the article

• Why does this sql statement keep saying it is a boolean and not a paramter? (php/Mysql)

  - by ggfan

  In this statement, I am trying to see if there if the latest posting in the database that has the exact same title, price, city, state, detail. If there is, then it would say to the user that the exact post has been already made; if not then insert the posting into the dbc. (This is one type of check so that users can't accidentally post twice. This may not be the best check, but this statement error is annoying me, so I want it to work :)) Why won't this sql work? I think it's not letting the title=$title and not getting the value in the $title... ERROR: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in postad.php on line 365 //there is a form that users fill out that has title, price, city, etc <form> blah blah </form> //if users click submit, then does all the checks and if all okay, insert to dbc if (isset($_POST['submit'])) { // Grab the pposting data from the POST and gets rid of any funny stuff $title = mysqli_real_escape_string($dbc, trim($_POST['title'])); $price = mysqli_real_escape_string($dbc, trim($_POST['price'])); $city = mysqli_real_escape_string($dbc, trim($_POST['city'])); $state = mysqli_real_escape_string($dbc, trim($_POST['state'])); $detail = mysqli_real_escape_string($dbc, trim($_POST['detail'])); if (!is_numeric($price) && !empty($price)) { echo "<p class='error'>The price can only be numbers. No special characters, etc</p>"; } //Error problem...won't let me set title=$title, detail=$detail, etc. //this statement after all the checks so that none of the variables are empty $query="Select * FROM posting WHERE user_id={$_SESSION['user_id']} AND title=$title AND price=$price AND city=$city AND state=$state AND detail=$detail"; $data = mysqli_query($dbc, $query); if(mysqli_num_rows($data)==1) { echo "You already posted this ad. Most likely caused by refreshing too many times."; } }

  Read the article

• solving problems recursively in C

  - by Harry86

  Our professor gave us the following assignment: A "correct" series is one inwhich the sum of its members equals to the index of its first member. The program is supposed to find the length of the LONGEST "correct" series within a series of n numbers. for example: if the input series would be arr[4]={1, 1, 0, 0} the output (longest "correct" series) would be 3. arr[0]=1. 0!=1 therefore the longest series here is 0. arr[1]=1,and 1=1. but the follwing members also sum up to 1 as shown below: 1=arr[1]+arr[2]+arr[3] = 1+ 0 + 0, therefore the longest series here is 3. the output in this example is 3. That's what I got so far: int solve(int arr[], int index, int length,int sum_so_far) { int maxwith,maxwithout; if(index==length) return 0; maxwith = 1+ solve(arr,index+1,length,sum_so_far+arr[index]); maxwithout = solve(arr,index+1,length,arr[index+1]); if(sum_so_far+arr[index]==index) if(maxwith>maxwithout) return maxwith; return maxwithout; return 0; } int longestIndex(int arr[], int index,int length) { return solve(arr,0,length,0); } What am I doing wrong here? Thanks a lot for your time... Harry

  Read the article

• C++ Loop - Need variable to accumulate sum

  - by user1780064

  I'm writing a program to ask the user to enter a value between 5 and 21 (inclusive). If the number entered is not in this range, it prints, "Please try again". If the number is within the range, I need to take that number, and print the sum of all the numbers from 1 to the value entered. So if the user entered "7", the sum would be "28". I successfully wrote the first loop, in the case of the number not being within the range, but cannot figure out how to run the second loop- whether to use a while, do-while, or for loop. Please advise. #include <iostream> int main () { int uservalue; int count; int sum; //Prompt user for input do { cout << "Enter a value from 5 to 21: "; cin >> uservalue; if (uservalue < 5 || uservalue > 21) cout << "Value out of range. Try again..." << endl; } while (uservalue < 5 || uservalue > 21); cout << endl; //Loop to accumulate sum for (count = 1, count < uservalue, count++;) { sum = uservalue + count; if (uservalue <= 5 || uservalue <= 21) cout << the sum is " << sum << endl; } return 0; }

  Read the article

• Adding extra data to a Variable

  - by DogPooOnYourShoe

  Right now, my code plucks out only one value using Mysql. So I thought I might aswell add each found result to a variable, however I dont know how to do this. This must be a very basic question, but I cant find a answer for it echo '<table border="1">'; echo "<tr><td><b>Surname</b></td><td><b>Title/Name</b></td><td><b>Numbers</b></td><td><b>Telephone</b></td><td><b>Edit</b></td><td><b>Del</b></td></tr>\n"; while ($row= mysql_fetch_array($result)) { $Surname = $row["Surname"]; $Title = $row["TitleName"]; $Email = $row["Email"]; $Telephone = $row["Telephone"]; $id = $row["id"]; $MooringNumbers = $row['Number']; $Assignedto['AssignedTo']; } $MooringQuery = "select * FROM mooring WHERE AssignedTo='$id'"; $MooringResult = mysql_query($MooringQuery) or die("Couldn't execute query"); while ($row1= mysql_fetch_array($MooringResult)) { $AssignedTo = $row1["AssignedTo"]; $MooringNumbers = $row1["Number"]; echo '<tr><td>' .$Surname.'</td><td>'.$Title.'</td><td>'.$MooringNumbers . '</td><td>'.$Telephone.'</td><td>' . '<a href="rlayCustomerUpdtForm.php?id='.$id.'">[EDIT]</a></td>'.'<td>'. '<a href="deleteCustomer.php?id='.$id.'">[x]</a></td>'. '</tr>'; }

  Read the article

• Filtering string in Python

  - by Ecce_Homo

  I am making algorithm for checking the string (e-mail) - like "E-mail addres is valid" but their are rules. First part of e-mail has to be string that has 1-8 characters (can contain alphabet, numbers, underscore [ _ ]...all the parts that e-mail contains) and after @ the second part of e-mail has to have string that has 1-12 characters (also containing all legal expressions) and it has to end with top level domain .com EDIT email = raw_input ("Enter the e-mail address:") length = len (email) if length > 20 print "Address is too long" elif lenght < 5: print "Address is too short" if not email.endswith (".com"): print "Address doesn't contain correct domain ending" first_part = len (splitting[0]) second_part = len(splitting[1]) account = splitting[0] domain = splitting[1] for c in account: if c not in "abcdefghijklmopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.": print "Invalid char", "->", c,"<-", "in account name of e-mail" for c in domain: if c not in "abcdefghijklmopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.": print "Invalid char", "->", c,"<-", "in domain of e-mail" if first_part == 0: print "You need at least 1 character before the @" elif first_part> 8: print "The first part is too long" if second_part == 4: print "You need at least 1 character after the @" elif second_part> 16: print "The second part is too long" else: # if everything is fine return this print "E-mail addres is valid" EDIT: After reproting what is wrong with our input, now I need to make Python recognize valid address and return ("E-mail adress is valid") This is the best i can do with my knowledge....and we cant use regular expressions, teacher said we are going to learn them later.

  Read the article

• Why does this javascript code have an infinite loop?

  - by asdas

  optionElements is a 2d array. Each element has an array of length 2. These are an integer number and an element. I have a select list called linkbox, and i want to add all of the elements to the select list. The order I want them to go in is important, and is determined by the number each element has. It should be smallest to highest. So think of it like this: optionElements is: [ [5, <option>], [3, <option], [4, <option], [1, <option], [2, <option]] and it would add them to link box in order of those numbers. BUT that is not what happens. It is an infinite loop after the first time. I added the x constraint just to stop it from freezing my browser but you can ignore it. var b; var smallest; var samllestIndex; var x = 0; while(optionElements.length > 0 && ++x < 100) { smallestIndex = 0; smallest = optionElements[0][0]; b = 0; while( ++b < optionElements.length) { if(optionElements[b][0] > smallest) { smallestIndex = b; smallest = optionElements[b][0]; } } linkbox.appendChild(optionElements[smallestIndex][1]); optionElements.unshift(optionElements[smallestIndex]); } can someone point out to me where my problem is?

  Read the article

• Int - number too large. How to get program to fail?

  - by Dave

  Hi Problem: How do you get a program to fail if a number goes beyond the bounds of its type? This code below gives the wrong answer for sum of primes under 2 million as I'd used an int instead of a long. [TestMethod] public void CalculateTheSumOfPrimesBelow2million() { int result = PrimeTester.calculateTheSumOfPrimesBelow(2000000); // 2million Assert.AreEqual(1, result); // 1,179,908,154 .. this was what I got with an int... // correct answer was 142,913,828,922 with a long } public static class PrimeTester { public static int calculateTheSumOfPrimesBelow(int maxPrimeBelow) { // we know 2 is a prime number int sumOfPrimes = 2; int currentNumberBeingTested = 3; while (currentNumberBeingTested < maxPrimeBelow) { double squareRootOfNumberBeingTested = (double)Math.Sqrt(currentNumberBeingTested); bool isPrime = true; for (int i = 2; i <= squareRootOfNumberBeingTested; i++) { if (currentNumberBeingTested % i == 0) { isPrime = false; break; } } if (isPrime) sumOfPrimes += currentNumberBeingTested; currentNumberBeingTested += 2; // as we don't want to test even numbers } return sumOfPrimes; } }

  Read the article

• Quality questionnaire php mysql graphipcs

  - by Marcelo

  Hi, i'm making a questionnaire about a service quality, its contains the options (poor, regular, good, very good). It's contains 6 questions (radio button) and a suggestion box (textbox). In the table of the database i created 6 rows for questions, 1 for suggestion and 1 for date (a friend of mine tole me to use this but i didn't get why). q1) I'm going to atribute a value form 1 to 4 to the radio buttons options, and i'd like to sum every answer for each question, and then divide by the numbers of user that answered that question and give the mean. how am i supposed to to that? I'd also like generate reports of the month, of the year. q2) not only about the questionnaire but for registration too. I need all the fields to be completed, no blank options, if he don't complete all of fields it'll not be submitted and there will be a warning message to the user. q3) about the field type, i'd like it to be the same class that is in the database, i'm having a "problem". Ex: Name(varchar) : 1234(int), in the field 'name' of the table of the database 1234 will be shown as name, and i don't want this, i want only the type that i declared in the construction of the table. q4) i'd also like to know if it's possible to create pizza graphics, about the percentage of each question, is this possible? q5) I'm using phpmyadmin and some of my id's are auto_increment, but 'cause of my tests they at a high number, i'd like to restart to 0 the ids number, is this possible? Thanks for the attention.

  Read the article

• Porting Python algorithm to C++ - different solution

  - by cb0

  Hello, I have written a little brute string generation script in python to generate all possible combinations of an alphabet within a given length. It works quite nice, but for the reason I wan't it to be faster I try to port it to C++. The problem is that my C++ Code is creating far too much combination for one word. Heres my example in python: ./test.py gives me aaa aab aac aad aa aba .... while ./test (the c++ programm gives me) aaa aaa aaa aaa aa Here I also get all possible combinations, but I get them twice ore more often. Here is the Code for both programms: #!/usr/bin/env python import sys #Brute String Generator #Start it with ./brutestringer.py 4 6 "abcdefghijklmnopqrstuvwxyz1234567890" "" #will produce all strings with length 4 to 6 and chars from a to z and numbers 0 to 9 def rec(w, p, baseString): for c in "abcd": if (p<w - 1): rec(w, p + 1, baseString + "%c" % c) print baseString for b in range(3,4): rec(b, 0, "") And here the C++ Code #include <iostream> using namespace std; string chars="abcd"; void rec(int w,int b,string p){ unsigned int i; for(i=0;i<chars.size();i++){ if(b < (w-1)){ rec(w, (b+1), p+chars[i]); } cout << p << "\n"; } } int main () { int a=3, b=0; rec (a+1,b, ""); return 0; } Does anybody see my fault ? I don't have much experience with C++. Thanks indeed

  Read the article

• one more time about loop that doesn't work

  - by unit

  I have asked a couple of questions about this for loop: String[] book = new String [ISBN_NUM]; bookNum.replaceAll("-",""); if (bookNum.length()!=ISBN_NUM) throw new ISBNException ("ISBN "+ bookNum + " must be 10 characters"); for (int i=0;i<bookNum.length();i++) { if (Character.isDigit(bookNum.charAt(i))) book[j]=bookNum.charAt(i); //this is the problem right here j++; if (book[9].isNotDigit()|| book[9]!="x" || book[9]!="X") throw new ISBNException ("ISBN " + bookNum + " must contain all digits" + "or 'X' in the last position"); } which will not compile. An answer I had from the other question I asked told me that the line where the error occurs is wrong in that bookNum.charAt(i) is an (immutable) string, and I can't get the values into a book array that way. What I need to do on my assignment is check an ISBN number (bookNum) to see that it is all numbers, except the last digit can be an 'x' (valid ISBN). Is this the best way to do it? If so, what the hell am I doing wrong? If not, what method would be a better one to use?

  Read the article

• Python lists/arrays: disable negative indexing wrap-around

  - by wim

  While I find the negative number wraparound (i.e. A[-2] indexing the second-to-last element) extremely useful in many cases, there are often use cases I come across where it is more of an annoyance than helpful, and I find myself wishing for an alternate syntax to use when I would rather disable that particular behaviour. Here is a canned 2D example below, but I have had the same peeve a few times with other data structures and in other numbers of dimensions. import numpy as np A = np.random.randint(0, 2, (5, 10)) def foo(i, j, r=2): '''sum of neighbours within r steps of A[i,j]''' return A[i-r:i+r+1, j-r:j+r+1].sum() In the slice above I would rather that any negative number to the slice would be treated the same as None is, rather than wrapping to the other end of the array. Because of the wrapping, the otherwise nice implementation above gives incorrect results at boundary conditions and requires some sort of patch like: def ugly_foo(i, j, r=2): def thing(n): return None if n < 0 else n return A[thing(i-r):i+r+1, thing(j-r):j+r+1].sum() I have also tried zero-padding the array or list, but it is still inelegant (requires adjusting the lookup locations indices accordingly) and inefficient (requires copying the array). Am I missing some standard trick or elegant solution for slicing like this? I noticed that python and numpy already handle the case where you specify too large a number nicely - that is, if the index is greater than the shape of the array it behaves the same as if it were None.

  Read the article

• adding elements in to the doubly linked list

  - by user329820

  Hi this is my code for main class and doubly linked class and node class but when I run the program ,in the concole will show this"datastructureproject.DoublyLinkedList@19ee1ac" instead of the random numbers .please help me thanks! main class: public class Main { public static int getRandomNumber(double min, double max) { Random random = new Random(); return (int) (random.nextDouble() * (max - min) + min); } public static void main(String[] args) { int j; int i = 0; i = getRandomNumber(10, 10000); DoublyLinkedList listOne = new DoublyLinkedList(); for (j = 0; j <= i / 2; j++) { listOne.add(getRandomNumber(10, 10000)); } System.out.println(listOne); } } doubly linked list class: public class DoublyLinkedList { private Node head ; private Node tail; private long size = 0; public DoublyLinkedList() { head= new Node(0, null, null); tail = new Node(0, head, null); } public void add(int i){ head.setValue(i); Node newNode = new Node(); head.setNext(newNode); newNode.setPrev(head); newNode = head; } } and the node class is like the class that you have seen before (Node prev,Node next,int value)

  Read the article

• Reading input files in FORTRAN

  - by lollygagger

  Purpose: Create a program that takes two separate files, opens and reads them, assigns their contents to arrays, do some math with those arrays, create a new array with product numbers, print to a new file. Simple enough right? My input files have comment characters at the beginning. One trouble is, they are '#' which are comment characters for most plotting programs, but not FORTRAN. What is a simple way to tell the computer not to look at these characters? Since I have no previous FORTRAN experience, I am plowing through this with two test files. Here is what I have so far: PROGRAM gain IMPLICIT NONE REAL, DIMENSION (1:4, 1:8) :: X, Y, Z OPEN(1, FILE='test.out', & STATUS='OLD', ACTION='READ') ! opens the first file READ(1,*), X OPEN(2, FILE='test2.out', & STATUS='OLD', ACTION='READ') ! opens the second file READ(2,*), Y PRINT*, X, Y Z = X*Y ! PRINT*, Z OPEN(3, FILE='test3.out', STATUS='NEW', ACTION='WRITE') !creates a new file WRITE(3,*), Z CLOSE(1) CLOSE(2) CLOSE(3) END PROGRAM PS. Please do not overwhelm me with a bunch of code monkey gobblety gook. I am a total programming novice. I do not understand all the lingo, that is why I came here instead of searching for help in existing websites. Thanks.

  Read the article

• Fixing an SQL where statement that is ugly and confusing

  - by Mike Wills

  I am directly querying the back-end MS SQL Server for a software package. The key field (vehicle number) is defined as alpha though we are entering numeric value in the field. There is only one exception to this, we place an "R" before the number when the vehicle is being retired (which means we sold it or the vehicle is junked). Assuming the users do this right, we should not run into a problem using this method. (Right or wrong isn't the issue here) Fast forward to now. I am trying to query a subset of these vehicle numbers (800 - 899) for some special processing. By doing a range of '800' to '899' we also get 80, 81, etc. If I cast the vehicle number into an INT, I should be able to get the right range. Except that these "R" vehicles are kicking me in the butt now. I have tried where vehicleId not like 'R%' and cast(vehicleId as int) between 800 and 899 however, I get a casting error on one of these "R" vehicles. What does work is where vehicleId not between '800' and '899' and cast(vehicleId as int) between 800 and 899', but I feel there has to be a better way and less confusing way. I have also tried other variations with HAVING and a sub-query all producing a casting error.

  Read the article

• transferring binary files between systems

  - by tim

  Hi guys I'm trying to transfer my files between 2 UNIX clusters, the data is pure numeric (vectors of double) in binary form. Unfortunately one of the systems is IBM ppc997 and the other is AMD Opteron, It seems the format of binary numbers in these systems are different. I have tried 3 ways till now: 1- Changed my files to ASCII format (i.e. saved a number at each line in a text file), sent them to the destination and changed them again to binary on the target system (they both are UNIX, no end of line character difference??!) 2- Sent pure binaries to the destination 3- used uuencode sent them to the destination and decoded them Unfortunately any of these methods does not work (my code in the destination system generates garbage, while it works on the first system, I'm 100% sure the code itself is portable). I don't know what else I can do? Do you have any idea? I'm not a professional, please don't use computer scientists terminology! And: my codes are in C, so by binary I mean a one to one mapping between memory and hard disk. Thanks

  Read the article

< Previous Page | 207 208 209 210 211 212 213 214 215 216 217 218  | Next Page >