instance-variables

I am following Michael Hartl's RoR tutorial, and it is covering the basics of password encryption. This is the User model as it currently stands: class User < ActiveRecord::Base attr_accessor :password attr_accessible :name, :email,: password, :password_confirmation email_regex = /^[A-Za-z0-9._+-]+@[A-Za-z0-9._-]+\.[A-Za-z0-9._-]+[A-Za-z]$/ #tests for valid email addresses. validates :name, :presence => true, :length => {:maximum => 50} validates :email, :presence => true, :format => {:with => email_regex}, :uniqueness => {:case_sensitive => false} validates :password, :presence => true,

I am trying to pass the variable dirpath into the export_data() function. Export data runs off of a double click on a button located on a widget. Why is dirpath printing as: `<Tkinter.Event instance at 0x8ade56c>` instead of the actual path? def export_data(dirpath): print 'exporting...' print str(dirpath) os.mkdir('/home/bigl/Desktop/Library') shutil.copytree(dirpath, output_path) When I run my code I get the error exporting... <Tkinter.Event instance at 0x8ade56c> Traceback (most recent call last): File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 1413, in __call__ return self.func(*args)

I'm trying to write this code to get the first initialCapacity prime numbers and then print them in sequence using java. It isn't working for two reasons, firstly I get the error 41: non-static variable listOfPrimeNumbers cannot be referenced from a static context when I try to run the program, but even when I change the variable to static and run the program, it will only print out "1". So it is only iterating the while loop in the constructor Primes once, and then stopping and I simply cannot find the problem there no matter how hard I look ! Would anyone be able to help me out please, even

Python 3.4.0a1 Windows 8.1 Class Created: class Bank(object): bankrupt = False Command entered in IDLE __main__ with the following results: >>> a = Bank() >>> b = Bank() >>> a.bankrupt False >>> b.bankrupt False >>> b.bankrupt = True >>> b.bankrupt True >>> a.bankrupt False Expected output: I expected a.bankrupt to change to True when I changed b.bankrupt since the variable bankrupt is defined for the entire class and not for a single instance (with self.bankrupt ) Why is this not happening? You assigned to a new attribute to the instance instead. To change a class attribute, assign directly

To be more explicit, I get a compile time error when I try accessing an instance variable when I create an object using (), but when I don't, the code compiles and runs as expected. Also, this problem only applies to the default constructor. I would like to understand why. using namespace std; #include <iostream> class Student { public: int gpa; Student() { gpa = 4; } Student( int x ) { gpa = x; } }; int main() { Student zero; Student sally( 2 ); Student jack(); cout << zero.gpa << endl; //prints 4 cout << sally.gpa << endl; // prints 2 cout << jack.gpa << endl; //error: request for member

I have declared this ivar in my ViewController.h #import <UIKit/UIKit.h> @interface FirstViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> { NSArray *sortedCountries; } @property (nonatomic, retain) NSArray *sortedCountries; @end In ViewController.m, sortedCountries does it's job in -(void)ViewDidLoad{} by storing the result of a sorted .plist. When -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {} is called below, sortedCountries returns (null) Why doesn't the value of sortedCountries remain? I added a retain