> For the complete documentation index, see [llms.txt](https://docs.1l.lol/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.1l.lol/basics/input.md).

# 输入

### cin 输入

```cpp
int a, b;
cin >> a >> b;            // 用空格或换行分隔
string s;
cin >> s;                 // 读一个单词，遇空格/换行停止
```

> 特性：`cin >>` 会自动跳过空白字符，所以读不了带空格的整行。

### 读入整行

```cpp
string line;
getline(cin, line);       // 读入一整行（含空格），string 用

char buf[100];
cin.getline(buf, 100);    // 读入一整行，字符数组用
```

混用 `cin >>` 和 `getline` 时，`cin >>` 会残留换行符，需要先吃掉：

```cpp
int n;
cin >> n;
cin.ignore();             // 吃掉换行符
string s;
getline(cin, s);
```

### scanf 输入（C 风格）

```cpp
#include <cstdio>
int a; double x; char ch;
scanf("%d%lf %c", &a, &x, &ch);   // 注意取地址符 &
char s[100];
scanf("%s", s);                    // 字符串不用 &
```

### 字符级输入

```cpp
char c = getchar();       // 读一个字符（含空格、换行）
```

### 小结

| 需求           | 写法                  |
| ------------ | ------------------- |
| 读数字/单词       | `cin >> x`          |
| 读整行（string）  | `getline(cin, s)`   |
| 读整行（char\[]） | `cin.getline(s, n)` |
| 格式化输入        | `scanf`             |


---

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