ObjC Question with CS193p assignment (handling variables)

Question

Ok, im working on Assignment 2B (HelloPolly) for the Stanford CS193P course work from Spring '09. Per the assignment, i invoke a new instance of the "PolygonShape" class that is used for storing the polygon sides in the awakefromNib method. I would like to directly access the number of sides of that instance (in this case polygon.numberOfSides) later on in the code but the issue i run into is that technically at compile time, polygon object is not created yet.
Here is my code:
// Awaking from Nib method for HelloPolly2B
- (void)awakeFromNib; {
// Invoking a new instance of PolygonShape known as polygon
PolygonShape *polygon = [[PolygonShape alloc] initWithNumberOfSides: [NumberOfSides.text integerValue] minimumNumberOfSides: 3 maximumNumberOfSides: 12];
NSLog(@"My Polygon: %@", [polygon name]);
// Decrease method activated by interface button.
- (IBAction)decrease:(id)sender {
NSLog(@"Decrease Method");
// Compile fails here since technically, polygon is undeclared
if (polygon.numberOfSides > polygon.minimumNumberOfSides){
polygon.numberOfSides - 1;
interfaceUpdate;
NSLog(polygon.numberOfSides);
So how could i do this? I would like to avoid using the interface label text since it seems like bad practice to use that as a variable. I appreciate any suggestions or ideas on how i can handel this problem.
Thank you!
Message was edited by: RombusRK, Did not wrap code in proper tag

Answer 1

Ray, Thanks for the warm welcome and the dead on answer! So its not that that the variable is not setup yet, but that its local to that method, i figured it was something simple.
After reading though your suggestion, i looked back over the code and realized i was already declaring a global variable. Then as part of the implementation i was trying to redeclare the variable rather than use the one i already had.
Here is my corrected code for anyones future reference.
controller.h
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "PolygonShape.h"
@interface Controller : NSObject {
IBOutlet UILabel *AngleInDegrees;
IBOutlet UILabel *AngleInRadians;
IBOutlet UILabel *NameOfPolygon;
IBOutlet UILabel *NumberOfSides;
IBOutlet UIButton *decreaseButton;
IBOutlet UIButton *increaseButton;
IBOutlet PolygonShape *shape;
- (IBAction)decrease:(id)sender;
- (IBAction)increase:(id)sender;
@end
controller.m
#import "Controller.h"
@implementation Controller
// Awaking from Nib method for HelloPolly2B
- (void)awakeFromNib; {
[shape initWithNumberOfSides: [NumberOfSides.text integerValue] minimumNumberOfSides: 3 maximumNumberOfSides: 12];
NSLog(@"My Polygon: %@", [shape name]);
void interfaceUpdate(){
- (IBAction)decrease:(id)sender {
NSLog(@"Decrease Method");
if (shape.numberOfSides > shape.minimumNumberOfSides){
shape.numberOfSides - 1;
interfaceUpdate;
NSLog(shape.numberOfSides);
- (IBAction)increase:(id)sender {
NSLog(@"Inrease Method");
@end