52 lines
1.3 KiB
Markdown
52 lines
1.3 KiB
Markdown
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# String::Reserve / Resize
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```cpp
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void Reserve(SizeType capacity);
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void Resize(SizeType newSize);
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void Resize(SizeType newSize, char fillChar);
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```
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管理字符串的内存和大小。
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**参数：**
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- `capacity` - 要预留的最小容量
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- `newSize` - 新的字符串长度
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- `fillChar` - 当扩展字符串时用于填充新增位置的字符，默认为 '\0'
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**返回：** 无
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**复杂度：**
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- `Reserve`：最坏 O(n)，仅在需要扩展容量时复制数据
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- `Resize`：O(n)，当 newSize > Length 时可能需要扩展
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**示例：**
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```cpp
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#include "XCEngine/Containers/String.h"
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#include <iostream>
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int main() {
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XCEngine::Containers::String s("Hi");
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// Reserve - 预分配内存
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s.Reserve(100);
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std::cout << "After Reserve(100), Capacity: " << s.Capacity() << std::endl;
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// 输出: After Reserve(100), Capacity: 100
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// Resize - 缩短字符串
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s.Resize(1);
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std::cout << "After Resize(1): " << s.CStr() << std::endl; // 输出: H
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// Resize - 扩展字符串，用 'X' 填充
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s.Resize(5, 'X');
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std::cout << "After Resize(5, 'X'): " << s.CStr() << std::endl; // 输出: HXXXX
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return 0;
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}
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```
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## 相关文档
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- [String 总览](string.md) - 返回类总览
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- [Length / Capacity](size.md) - 获取长度和容量
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- [Clear](clear.md) - 清空字符串
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