Question

I am very new to objective-c and having a problem to initialize an object in view controller. The problem I am having is that when setTemp method is called, “0” is printed on the screen instead of the value of cTemp I would like it to be. Can anyone help me on this problem?

Below are excerpts of the code I have.

SJT.h

#import <Foundation/Foundation.h>
#import <stdlib.h>
@interface SJT : NSObject {
int cTemp;
}
- (int) newTemp;
@end

SJT.m

#import "SJT.h"
@implementation SJT
- (int) newTemp
{
    cTemp =  25 + rand() % 8;
    return cTemp;
}
@end

SJTViewController.h

#import <UIKit/UIKit.h>
@class SJT;

@interface SJTViewController : UIViewController {
    IBOutlet UILabel *temp;
    SJT *sjt;
}

@property (retain, nonatomic) UILabel *temp;
@property (retain, nonatomic) SJT *sjt;

- (IBAction) setTemp: (id) sender;

@end

SJTViewController.m

#import "SJTViewController.h"
#import "SJT.h"

@implementation SJTViewController
@synthesize temp;
@synthesize sjt;



- (IBAction) setTemp: (id) sender
{
    NSString *tempText = [[NSString alloc] initWithFormat:@"%d",sjt.newTemp];
    temp.text = tempText;
    [tempText release];
}
.
.
.
@end

Answer 1

The problem is that you’re mistaking property syntax for a method call; i.e.

sjt.newTemp

would become a call to [sjt newTemp]. Which happens to be exactly what you want, except that you have not specified in your header/implementation that there actually is a property called newTemp.

So, in this scenario what you want to do is either a) define the property in the header:

@property(nonatomic, readonly) int newTemp;

or b), just call the method newTemp:

[sjt newTemp]