您可以在Objective-C中返回两个参数吗? [英] Can you return two arguments in objective-c?

问题描述

只是想知道您是否可以在目标c方法中返回两个参数，例如，我想返回一个笛卡尔坐标(x，y)，基本上是两个整数.创建类并返回实例的唯一方法是什么?还有别的我没想到的方法吗，这里是初学者.

Just wondering if you can return two arguments in an objective c method, for example I'd like to return a cartesian coordinate (x,y), basically two ints. is the only way to do this by creating a class and returning an instance? Is there some other way I'm not thinking of, kind of a beginner here.

(在语法上也将有所帮助.)

(Syntactical help would also be appreciated.)

谢谢

尼克

推荐答案

您只能从函数中返回一个值(就像C一样)，但是该值可以是任何值，包括结构.而且由于可以按值返回结构，因此可以定义一个这样的函数(借用您的示例):

You can only return one value from a function (just like C), but the value can be anything, including a struct. And since you can return a struct by value, you can define a function like this (to borrow your example):

-(NSPoint)scalePoint:(NSPoint)pt by:(float)scale
{
    return NSMakePoint(pt.x*scale, pt.y*scale);
}

这仅真正适用于小型/简单结构.

This is only really appropriate for small/simple structs.

如果要返回多个新的 object ，则函数应采用指向对象指针的指针，因此:

If you want to return more than one new object, your function should take pointers to the object pointer, thus:

-(void)mungeFirst:(NSString**)stringOne andSecond:(NSString**)stringTwo
{
    *stringOne = [NSString stringWithString:@"foo"];
    *stringTwo = [NSString stringWithString:@"baz"];
}

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