實例變量聲明錯誤？

Question

我的實例變量secondNumber沒有聲明自己。爲什麼不？ （我是編程新手，請耐心等待。） 在Xcode中，錯誤提示「解析問題：期望」;「 。在

// main.m 
// Subtraction 
// 
// Copyright 2012 __MyCompanyName__. All rights reserved. 
// 

#import <Foundation/Foundation.h> 

@interface NumberSub: NSObject 

{ 
int firstNumber 
int secondNumber 
int result 
} 
-(void) print; 
-(void) setFirstNumber: (int) f; 
-(void) setSecondNumber: (int) s; 
-(void) resetAll; 
-(void) printResult; 
@end 

@implementation NumberSub 

-(void) setFirstNumber: (int) f; 
{ 
firstNumber = f; 
} 

-(void) setSecondNumber: (int) s 
{ 
secondNumber = s; 
} 

-(void) print 
{ 
NSLog(@"%i - %i = ", firstNumber, secondNumber); 

} 

-(void) printResult 
{ 
NSLog(@"%i", firstNumber - secondNumber); 
} 

-(void) resetAll 
{ 
firstNumber = 0; 
secondNumber = 0; 
} 

@end 

int main (int argc, char *argv[]) 
{ 
NumberSub *subtractNumber = [[NumberSub = alloc]init]; 



[subtractNumber setFirstNumber: 10]; 
[subtractNumber setSecondNumber: 5]; 

[subtractNumber print]; 
[subtractNumber printResult]; 

[subtractNumber release]; 
return 0; 
} 

Answer 1

申報清單的最後，你忘了，在每個線

@interface NumberSub: NSObject 

{ 
    int firstNumber; 
    int secondNumber; 
    int result ; 
}