您如何正確撰寫@interface部分？

Question

我對Objective-C很新，並且創建了這個基本程序。它給我錯誤@interface部分，有沒有簡單的解釋，你可以給初學者如何建立@interface和@implementation部分？下面的程序有什麼問題？

#import <Foundation/Foundation.h> 

    @interface Rectangle : NSObject { 
    //declare methods 
    - (void) setWidth: (int) a; 
    - (void) setHieght: (int) b; 
    - (double) perimeter; 
    - (double) area; 

    } 
    @end 

    @implementation Rectangle 


    { 
    double area; 
    double perimeter; 
    int width; 
    int height; 
    } 
    - (void) setWidth: (int) a 
    { 
     width = a; 
    } 
    - (void) setHieght: (int) b 
    { 
    hieght = b; 
    } 

    @end 

    int main (int argc, const char * argv[]) 
    { 

    NSAutoreleasePool * Rectangle = [[NSAutoreleasePool alloc] init]; 
    int a = 4 
    int b = 5 
    int area = a * b; 
    int perimeter = 2 * (a +b); 

    NSLog(@"With width of %i and Hieght of %i", a, b); 
    NSLog(@"The perimeter is %i", perimeter); 
    NSLog(@"The Area is %i", area); 

    [pool drain]; 
    return 0; 
    } 

Answer 1

您的列表您的方法，艾瓦爾應該去。它應該是：

@interface Rectangle : NSObject { 

    //instance variables here 
} 

// declare methods or properties here 
- (void) setWidth: (int) a; 
- (void) setHieght: (int) b; 
- (double) perimeter; 
- (double) area; 

@end 

正如已經指出的那樣，您可以簡單地刪除花括號。

Answer 2

有在你的代碼的幾個問題，我們將在後面看到他們，但作爲初學者，你需要知道的幾件事情：

• main()是在你的項目main.m類，不要亂行動與在這裏和那裏，用init()代替
• 你不要在{}您@implementaion
• 範圍申報方法應該寫成
的 @implementation沒有什麼要執行 @end後
• @implementation不應在{}範圍，因爲它與@end
• 而一些更月底爲界，在這裏找到它http://www.slideshare.net/musial-bright/objective-c-for-beginners

所以你應該是這樣的：

#import <Foundation/Foundation.h> 

@interface Rectangle : NSObject 

//declare methods 
- (void) setWidth: (int) a; 
- (void) setHieght: (int) b; 
- (double) perimeter; 
- (double) area; 

@end 

@implementation Rectangle 

{ 雙倍面積;雙週長; int width; int height; }

- (void) setWidth: (int) a { 
    width = a; 
} 

- (void) setHieght: (int) b { 
    height = b; 
} 

- (id)init 
{ 
    self = [super init]; 
    if (self) { 
     // Custom initialization 
     int a = 4; 
     int b = 5; 
     int area = a * b; 
     int perimeter = 2 * (a +b); 

     NSLog(@"With width of %i and Hieght of %i", a, b); 
     NSLog(@"The perimeter is %i", perimeter); 
     NSLog(@"The Area is %i", area); 
    } 
    return self; 
} 

@end