easiest way to access a variable in another class

i declare a variable in one class and want to use that variable in the same class but i want to put data into the variable in a different class. How can i fill a variable from another class?

EDIT:

I have this in one class:

NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];
NSString *aString = [[managedObject valueForKey:@"data"] description];

Then i have this in another class:

    NSString *stalklabel = aString;

    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://news.search.ya开发者_JAVA百科hoo.com/rss?ei=UTF-8&p=%@&fr=news-us-ss", stalklabel, nil]];

Make a property / setter method to set the variable:

In the .h

@property(nonatomic, assign) int myInt;

In the .m

@synthesize myInt;

In your first class create a method that returns that string.

+ (NSString*)dataName {
    NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];
    NSString *aString = [[managedObject valueForKey:@"data"] description];
}

In the second class, call that method.

- (void)whatEverClass {
    NSString *stalklabel = [FirstClass dataName];

    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://news.search.yahoo.com/rss?ei=UTF-8&p=%@&fr=news-us-ss", stalklabel, nil]];
}

The stuff about properties is all true. The missing piece is a way for one class to talk to another. I do this all the time as follows:

Suppose I have a class called "First", and a class "Second". In my "First" class, I want to be able to access the "myInt" varable inside the "Second" class.

I would declare "Second" as such:

@class FirstClass; // Forward Declaration
@interface SecondClass: NSObject {
  FirstClass*first;
}

@property (nonatomic,retain) FirstClass *first;

Now, whereever I created secondClass (say in this case it was inside firstClass, but it doesn't have to be), I'd do something like"

SecondClass *second = [[SecondClass alloc] init];
[second setFirst: self];

Then inside "second" code, you can do:

[first setMyInt:123];