外企iOS开发的笔试题

一组外企iOS开发的笔试题，您能回答出来吗？从群里收集来的。

（miki西游@mikixiyou的文档，原文链接: http://mikixiyou.iteye.com/blog/1546376  转载请注明出处和作者）

1 why can‘t NSArray contain NSInteger Instance? with which extra step can you do it?
2.complete this code so that it becomes syntacticallty correct using no more than one additional word and  square branckets NsInteger myNumber=@"10000";

这个我会回答是：

NSInteger myInt = [myString intValue];

3.What does the following code do? Variable age is defined as NSInteger It compiles fine..but why does it crash? UILabel *mylabel=[UILabel new]; mylabel.text=age?[NSString stringWithFormat:@"%@",age];@"";

这个我的回答是：定义一个UITable对象，根据age的true或者false来给该对象的text属性赋值。难道是bool转换成string时导致的crash?
4.Why does the following code crash as soon as the property is set?What is the simple fix? MeasueStripView.h @Interface MeasueLinealView:UIview { NSUIInteger minvalue;
} @property (nonatomic,assign)NSUIInteger minvalue;
MeasueStripView.m #import "MeasueStripView.h" @implementation MeasueStripView @synthsize minvalue #progma mark Passthrough properties -(void) setMinValue:(NSUIInteger)aVal {
self.minvalue:aVal; } Some other file: MeasueStripView *myMS=[MeasueStripView ww]； myMS.minValue=100;//THis Line crashes..
5.You have a UIView and would like to for it to have rounded corners, What‘s the Fastest way to achive that|
6 How many methods do you know of performing a piece of code in other thread on IOS4.0 and later version.

关于多线程的问题，只能去翻apple的文档了。

我查到的方法是： 1、detachNewThreadSelector或performSelectorInBackground 2、NSThread 3、NSOperationQueue