如何在 Objective-C 中将对象添加到数组中？

Question

我开始用 Objective-C 编程。我正在使用一本书来学习第一基础知识。给定的示例不起作用！我在代码中看不到问题。
理解它并不难，但就是行不通。但我在其他地方找到的所有东西，他们都像我一样添加了对象。
不知道语法有没有改变？我正在使用 iOS 4.3 SDK 和 Xcode 3.2.6！？
这部分失败：

[questions addObject: @”What is 7 + 7?”]; //FAILS
[answers addObject: @”14”];

错误消息显示：
/Applications/Quiz/Classes/QuizAppDelegate.m:32:0
应用程序/测验/类/QuizAppDelegate.m：32：错误：“@”标记之前的预期表达式

如果有人可以帮助我，我会非常高兴！ 谢谢你！

我也附上了代码！

Jules

完整代码：.h:

#import <UIKit/UIKit.h>

@interface QuizAppDelegate : NSObject <UIApplicationDelegate> {

    int currentQuestionIndex;

    //The model objects
    NSMutableArray *questions;
    NSMutableArray *answers;

    //The view objects
    IBOutlet UILabel *questionField;
    IBOutlet UILabel *answerField;

    UIWindow *window;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;

-(IBAction)showQuestion:(id)sender;
-(IBAction)showAnswer:(id)sender;

@end

失败的部分代码：.m:

#import "QuizAppDelegate.h"

@implementation QuizAppDelegate

@synthesize window;

-(id)init{

    // Call the init method implemented by the superclass 
    [super init];

    // Create two arrays and make the pointers point to them 
    questions = [[NSMutableArray alloc] init]; 
    answers = [[NSMutableArray alloc] init];

    // Add questions and answers to the arrays 
    [questions addObject: @”What is 7 + 7?”]; //FAILS
    [answers addObject: @”14”];

    [questions addObject: @”Was ist die Hauptstadt von Madagaskar?”]; //FAILS
    [answers addObject: @”Antananarivo”];

    [questions addObject: @”Was ergibt 5-2*2+6?”]; //FAILS
    [answers addObject: @”7”];

    // Return the address of the new object 
    return self;

}

-(IBAction)showQuestion:(id)sender{

//Step to the next question
currentQuestionIndex++;

//Am I past the last question?
if(currentQuestionIndex==[questions count]){

    //Go back to the first question
    currentQuestionIndex=0;
}

// Get the string at that index in the questions array 
NSString *question = [questions objectAtIndex:currentQuestionIndex];

//Log the string to the console
NSLog(@"displaying question:%@",question);

//Display the string in the question field
[questionField setText:question];

//Clear the answer field
[answerField setText:@"???"];
}

-(IBAction)showAnswer:(id)sender{

//What is the answer to the current question
NSString *answer=[answers objectAtIndex:currentQuestionIndex];

//Display it in the answer field
[answerField setText:answer];
} 

Answer 1

我认为，您在双引号“中使用了假字符，就像您的一样”。您是否从某处复制并粘贴了代码？

Answer 2

或者甚至更短：

[myArray addObject:[NSString stringWithString:@"Wie hoch ist der Eiffelturm?"]];