在Objective-C中切换语句和实例变量分配

在switch语句中创建新的局部变量似乎有问题.我以为这是我的类头文件,但是甚至在尝试分配一个新的NSObject时收到错误.这是我的语法： @H_502_2@-(NSArray *)charactersFromChapter:(NSInteger)number { NSObject *noError = [[NSObject alloc] init]; //line above does not cause error NSArray *characters; switch (number) { case 1: NSObject *obj = [[NSObject alloc] init]; //error happens in line above (Expected expression) characters = [NSArray arrayWithObject:obj]; break; case 2: break; case 3: break; } return characters; }