这是＆QUOT - →;＆QUOT;在目标C？ [英] What is "->" in Objective C?

问题描述

我已经看到了这个运营商弹出在例如code好几次在学在Mac上Objective C的。

I've seen this operator pop up quite a few times in example code in "Learn Objective C on the Mac."

我相信这是在目标C继承了C语言的操作员。
我想谷歌搜索和搜索堆栈溢出，并没有什么奇怪的来到了。

I believe it's an operator in the C language which Objective C inherits. I tried Googling and searching Stack Overflow and oddly nothing came up.

它有一个英文名字？

推荐答案

它与结构来做。

当我们在栈上有本地可用一个结构，我们访问其成员与。运营商。例如：

When we have a struct available locally on the stack, we access its members with the . operator. For example:

CGPoint p = CGPointMake(42,42);
NSLog(@"%f", p.x);

不过，如果我们不是有一个的指针的一个结构，我们必须使用 - ＆GT; 运营商：

However, if we instead have a pointer to a structure, we have to use the -> operator:

CGPoint *p = malloc(1*sizeof(CGPoint));
p->x = 42.0f;
NSLog(@"%f", p->x);
free(p);

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