Document on Aminiam's Blog

`printf` `scanf` Format Quick Lookup

Wed, 02 Sep 2026 13:59:38 +0800

一、格式说明符

格式符	printf 参数类型	scanf 参数类型	说明
`%d`	`int`	`int*`	十进制有符号整数
`%u`	`unsigned int`	`unsigned int*`	十进制无符号整数
`%o`	`unsigned int`	`unsigned int*`	八进制
`%x`	`unsigned int`	`unsigned int*`	十六进制（小写）
`%X`	`unsigned int`	`unsigned int*`	十六进制（大写）
`%f`	`double`	`float*`	浮点数（printf 用 `%f`/`%lf` 均可，scanf 必须 `%f` 给 float，`%lf` 给 double）
`%e`	`double`	`float*`	科学计数法（小写 e）
`%g`	`double`	`float*`	自动选 `%f` 或 `%e`（较短）
`%c`	`char`	`char*`	单个字符
`%s`	`const char*`	`char[]`	字符串（遇空白停止）
`%p`	`const void*`	`void**`	指针地址（十六进制）
`%n`	`int*`	`int*`	写入已输出/读取的字符数
`%%`	-	-	输出字面量 `%`

二、长度修饰符

修饰符	适用类型示例	格式
`hh`	`signed char` / `unsigned char`	`%hhd`, `%hhu`
`h`	`short` / `unsigned short`	`%hd`, `%hu`
`l`	`long` / `unsigned long`	`%ld`, `%lu`
`ll`	`long long` / `unsigned long long`	`%lld`, `%llu`
`L`	`long double`	`%Lf`, `%Le`
`z`	`size_t`	`%zd`
`t`	`ptrdiff_t`	`%td`

三、`printf`常用标志

标志	作用	示例（`%`后加标志）
`-`	左对齐（默认右对齐）	`%-10d`
`+`	强制显示正负号	`%+d`
空格	正数前加空格	`% d`
`#`	八进制前加`0`，十六进制加`0x`/`0X`，浮点数强制小数点	`%#o`, `%#x`, `%#f`
`0`	用 `0` 填充宽度（而非空格）	`%08d`

四、宽度与精度

格式	含义	示例
`%最小宽度d`	输出至少占 n 位，不足补空格	`%5d`
`%.精度f`	小数位数（浮点）/ 最大字符数（字符串）/ 最少数字位数（整数）	`%.2f`, `%.5s`
`%.f`	宽度和精度由参数提供	`printf("%.f", w, p, val);`

五、scanf 特殊用法

用法	说明	示例
`*`	抑制赋值（跳过）	`scanf("%*d %d", &n);`
`[集合]`	只读指定字符集	`%[a-z]`（读小写字母）
`[^]`	读直到遇到某字符	`%[^,]`（读逗号前）

CPP __Builtin_

Wed, 02 Sep 2026 13:52:32 +0800

CPP Builtin

1. 位运算与计数

函数	功能描述	示例	注意
`__builtin_popcount(x)`	返回 `x` 的二进制中 1 的个数	`__builtin_popcount(15)` → `4`	有 `popcountl`、`popcountll` 版本
`__builtin_clz(x)`	返回从最高位开始的前导零个数	`__builtin_clz(1)`（32位）→ `31`	传入 `0` 是未定义行为；有 `clzl`、`clzll`
`__builtin_ctz(x)`	返回从最低位开始的尾随零个数	`__builtin_ctz(8)` → `3`	传入 `0` 是未定义行为；有 `ctzl`、`ctzll`
`__builtin_ffs(x)`	返回最低位 1 的位置（从 1 开始）	`__builtin_ffs(8)` → `4`	`x=0` 时返回 `0`；有 `ffsl`、`ffsll`
`__builtin_parity(x)`	返回 1 的个数的奇偶性（奇数个1→1）	`__builtin_parity(15)` → `0`	有 `parityl`、`parityll`

2. 算术运算与安全

函数	功能描述	示例	注意
`__builtin_add_overflow(a, b, &res)`	安全加法，检测是否溢出	溢出返回 `true`，否则存入 `res` 并返回 `false`	支持 `sub`（减法）和 `mul`（乘法）
`__builtin_abs(x)` 等	计算整数或浮点数的绝对值	`__builtin_abs(-10)` → `10`	有 `labs`、`llabs`、`fabs` 等版本

3. 优化与调试

函数	功能描述	示例	注意
`__builtin_expect(exp, c)`	提供分支预测信息，优化代码布局	常与 `if` 结合，如 `if (__builtin_expect(ptr == nullptr, 0))`	错误使用可能降低性能
`__builtin_trap()`	强制执行陷阱指令，程序异常终止	用于不应执行到的代码路径	–
`__builtin_unreachable()`	告诉编译器某路径永远不会执行，辅助优化	常用于 `switch` 的 `default` 分支（当所有情况已覆盖）	–

VS Code Task: Commit and Push

Tue, 18 Aug 2026 20:31:10 +0800

Commands

Add in {PROJECT_SOURCE_DIR}/.vscode/tasks.json:

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{
 "tasks": [
 {
 "label": "Commit & Push",
 "type": "shell",
 "command": "git add . && git commit -m \"$(date '+%Y-%m-%d %H:%M:%S')\" && git push",
 "problemMatcher": []
 }
 ]
}

Update the fork

Tue, 18 Aug 2026 20:21:46 +0800

Commands

Update to the latest

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hugo mod get -u github.com/CaiJimmy/hugo-theme-stack/v4
hugo mod tidy

Update to specific version

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hugo mod get github.com/CaiJimmy/hugo-theme-stack/v4@v4.1.0

Markdown Syntax Guide

Thu, 07 Sep 2023 00:00:00 +0000

This article offers a sample of basic Markdown syntax that can be used in Hugo content files, also it shows whether basic HTML elements are decorated with CSS in a Hugo theme.

Headings

The following HTML <h1>—<h6> elements represent six levels of section headings. <h1> is the highest section level while <h6> is the lowest.

H1

H2

H3

H4

H5

H6

Paragraph

Xerum, quo qui aut unt expliquam qui dolut labo. Aque venitatiusda cum, voluptionse latur sitiae dolessi aut parist aut dollo enim qui voluptate ma dolestendit peritin re plis aut quas inctum laceat est volestemque commosa as cus endigna tectur, offic to cor sequas etum rerum idem sintibus eiur? Quianimin porecus evelectur, cum que nis nust voloribus ratem aut omnimi, sitatur? Quiatem. Nam, omnis sum am facea corem alique molestrunt et eos evelece arcillit ut aut eos eos nus, sin conecerem erum fuga. Ri oditatquam, ad quibus unda veliamenimin cusam et facea ipsamus es exerum sitate dolores editium rerore eost, temped molorro ratiae volorro te reribus dolorer sperchicium faceata tiustia prat.

Itatur? Quiatae cullecum rem ent aut odis in re eossequodi nonsequ idebis ne sapicia is sinveli squiatum, core et que aut hariosam ex eat.

Blockquotes

The blockquote element represents content that is quoted from another source, optionally with a citation which must be within a footer or cite element, and optionally with in-line changes such as annotations and abbreviations.

Blockquote without attribution

Tiam, ad mint andaepu dandae nostion secatur sequo quae. Note that you can use Markdown syntax within a blockquote.

Blockquote with attribution

Don’t communicate by sharing memory, share memory by communicating.
— Rob Pike¹

Tables

Tables aren’t part of the core Markdown spec, but Hugo supports supports them out-of-the-box.

Name	Age
Bob	27
Alice	23

Inline Markdown within tables

Italics	Bold	Code
italics	bold	`code`

A	B	C	D	E	F
Lorem ipsum dolor sit amet, consectetur adipiscing elit.	Phasellus ultricies, sapien non euismod aliquam, dui ligula tincidunt odio, at accumsan nulla sapien eget ex.	Proin eleifend dictum ipsum, non euismod ipsum pulvinar et. Vivamus sollicitudin, quam in pulvinar aliquam, metus elit pretium purus	Proin sit amet velit nec enim imperdiet vehicula.	Ut bibendum vestibulum quam, eu egestas turpis gravida nec	Sed scelerisque nec turpis vel viverra. Vivamus vitae pretium sapien

Code Blocks

Code block with backticks

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<!doctype html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>Example HTML5 Document</title>
</head>
<body>
 <p>Test</p>
</body>
</html>

Code block indented with four spaces

<!doctype html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>Example HTML5 Document</title>
</head>
<body>
 <p>Test</p>
</body>
</html>

Diff code block

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[dependencies.bevy]
git = "https://github.com/bevyengine/bevy"
rev = "11f52b8c72fc3a568e8bb4a4cd1f3eb025ac2e13"
- features = ["dynamic"]
+ features = ["jpeg", "dynamic"]

One line code block

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<p>A paragraph</p>

List Types

Ordered List

First item
Second item
Third item

Unordered List

List item
Another item
And another item

Nested list

Fruit
- Apple
- Orange
- Banana
Dairy
- Milk
- Cheese

Other Elements — abbr, sub, sup, kbd, mark

GIF is a bitmap image format.

H₂O

Xⁿ + Yⁿ = Zⁿ

Press CTRL + ALT + Delete to end the session.

Most salamanders are nocturnal, and hunt for insects, worms, and other small creatures.

The above quote is excerpted from Rob Pike’s talk during Gopherfest, November 18, 2015. ↩︎

Shortcodes

Fri, 25 Aug 2023 00:00:00 +0000

For more details, check out the documentation.

Bilibili video

Tencent video

YouTube video

Generic video file

Your browser doesn't support HTML5 video. Here is a link to the video instead.

GitLab

Quote

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
― A famous person, The book they wrote

Photo by Codioful on Unsplash

Math Typesetting

Thu, 24 Aug 2023 00:00:00 +0000

Stack has built-in support for math typesetting using KaTeX.

It’s not enabled by default side-wide, but you can enable it for individual posts by adding math: true to the front matter. Or you can enable it side-wide by adding math = true to the params.article section in config.toml.

Inline math

This is an inline mathematical expression: $\varphi = \dfrac{1+\sqrt5}{2}= 1.6180339887…$

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$\varphi = \dfrac{1+\sqrt5}{2}= 1.6180339887…$

Block math

$$ \varphi = 1+\frac{1} {1+\frac{1} {1+\frac{1} {1+\cdots} } } $$

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$$
 \varphi = 1+\frac{1} {1+\frac{1} {1+\frac{1} {1+\cdots} } } 
$$

$$ f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi $$

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$$
 f(x) = \int_{-\infty}^\infty\hat f(\xi)\,e^{2 \pi i \xi x}\,d\xi
$$

Document on Aminiam's Blog

`printf` `scanf` Format Quick Lookup

一、格式说明符

二、长度修饰符

三、printf常用标志

四、宽度与精度

五、scanf 特殊用法

CPP __Builtin_

CPP Builtin

1. 位运算与计数

2. 算术运算与安全

3. 优化与调试

VS Code Task: Commit and Push

Commands

Update the fork

Commands

Update to the latest

Update to specific version

Markdown Syntax Guide

Headings

H1

H2

H3

H4

H5

H6

Paragraph

Blockquotes

Blockquote without attribution

Blockquote with attribution

Tables

Inline Markdown within tables

Code Blocks

Code block with backticks

Code block indented with four spaces

Diff code block

One line code block

List Types

Ordered List

Unordered List

Nested list

Other Elements — abbr, sub, sup, kbd, mark

Shortcodes

Bilibili video

Tencent video

YouTube video

Generic video file

GitLab

Quote

Math Typesetting

Inline math

Block math

三、`printf`常用标志