如何在目标C(iPhone)中通过引用传递值 [英] How to pass values by reference in objective C (iphone)

问题描述

我有一个非常基本的问题.我是新来的iPhone程序员. 我的问题是谁能告诉我如何通过引用obj中的函数来传递值. C?我知道如何在VB和C#中执行此操作.但是不知道在Obj c中怎么做.

I have a very basic question. I'm a new iPhone programmer. My question is can anybody tell me how can I pass values by reference to a function in obj. C? I know how to do it in VB and C#. But don't know how to do it in Obj c.

谢谢

推荐答案

Objective-C中的按引用传递与C中的传递引用相同.

Pass-by-reference in Objective-C is the same as it is in C.

等效于以下C#代码:

void nullThisObject(ref MyClass foo)
{
    foo = null;
}

MyClass bar = new MyClass();
this.nullThisObject(ref bar);
assert(bar == null);

是

- (void)nilThisObject:(MyClass**)foo
{
    [*foo release];
    *foo = nil;
}

MyClass* bar = [[MyClass alloc] init];
[self nilThisObject:&bar];
NSAssert(bar == nil);

和

- (void)zeroThisNumber:(int*)num
{
    *num = 0;
}

int myNum;
[self zeroThisNumber:&myNum];
NSAssert(myNum == 0);

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