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使用 *T 表示单项指针

准确指向一个值。

使用 *T 表示单项指针 是 CoddyKit 上的免费 Zig Academy 课时。这是第 1 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Zig Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Zig Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

A Pointer Points

A pointer holds the address of a value living somewhere else in memory, instead of holding the value itself. 📍

The *T Type

A single-item pointer has the type *T, where T is what it points at. So *i32 means a pointer to one i32 value.

var p: *i32 = undefined;

Take an Address

Use the & operator in front of a variable to get a pointer to it. The result is the address where that value is stored.

var x: i32 = 10;
const p = &x;

One Value Only

A single-item pointer guarantees it refers to exactly one value, not an array. The compiler tracks that for you.

Pointers Have a Size

A pointer is just an address, so its size is the machine word, not the size of T. Pointing at a huge struct still costs one address.

Mutable by Default

A plain *T lets you both read and write the value it points to. You will add const later to make it read-only.

var n: i32 = 1;
const p: *i32 = &n;

Pointers Share, Not Copy

Passing a pointer to a function shares the original value, so changes made through it are visible to the caller.

fn bump(p: *i32) void {
    p.* += 1;
}

Address of a const

Taking &x on a const gives you a *const i32, because Zig will not let you write through a pointer to immutable data.

const x: i32 = 5;
const p = &x;

Pointers Are Never Null

An ordinary Zig pointer can never be null. If a value might be missing you must use an optional pointer like ?*T.

Type Inference Helps

When you write const p = &x, Zig infers the pointer type from x, so you rarely have to spell out *i32 by hand.

var score: u8 = 42;
const p = &score;

Why Use Pointers

Pointers let you modify a value in place and avoid copying large data, which is core to Zig's explicit low-level control.

Quick Check

You want a function to change a caller's variable. What type should the parameter be?

Recap

A single-item pointer *T holds the address of exactly one value, is taken with &, is never null, and lets you share data instead of copying it. 🎯

常见问题解答

「使用 *T 表示单项指针」课时是免费的吗？

是的 — 「使用 *T 表示单项指针」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Zig Academy 课程的其余内容，请升级到 CoddyKit PRO。 Zig Academy 课程共包含 4 节课。

「使用 *T 表示单项指针」这节课中我会学到什么？

准确指向一个值。你通过在浏览器中直接运行的动手代码来练习 Zig Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Zig Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Zig Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 1 节课，共 4 节。

「使用 *T 表示单项指针」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Zig Academy 课中编写并运行代码吗？

能。每节 Zig Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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