String

• 常見操作

  bool empty() const
  size_type size() const
  size_type length() const
  size_type max_size() const
  size_type capacity() const
  void resever()
  void resever(size_type numbers)
  void shrink_to_fit()

• 產生C-String和字符數組

  const char* c_str() const
  const char* data() const

• 添加字符

  String& operator+=(const String& str)
  String& append(const String& str)
  String& operator+=(const char* cstr)
  String& append(const char* cstr)
  String& append(size_type num,char c)
  String& operator+=(char c)
  String& push_back(char c)
   
  

• 安插字符

  String& insert(size_type idx,const String& str)
  String& insert(size_type idx,const char* str)

• 刪除字符

  void clear()
  String& erase()
  String& erase(size_type idx)
  void pop_back()

• 替換字符

  String& replace(size_type idx,size_type len,const String& str)
  String& replace(Iterator beg,Iterator end,const String& str)
  String& replace(size_type idx,size_type len,const char* str)
   
  

• 查找
  ```
  size_type find(char c) const
  size_type find(char c,size_type idx) const
  size_type rfind(char c) const
  size_type rfind(char c,size_type idx) const //從idx位置開始查找

size_type find(const String& str) const
size_type find(const String& str,size_type idx) const
size_type rfind(const String& str)
size_type rfind(const String& str,size_type idx) const

size_type find(const char* str) const
size_type find(const char* str,size_type idx) const
size_type rfind(const char* str)
size_type rfind(const char* str,size_type idx) const

查找第一個符合條件的字符
size_type find_first_of(const String& str) const
size_type find_first_of(const String& str,size_type idx) const
size_type find_first_not_of(const String& str) const
size_type find_first_not_of(const String& str,size_type idx) const

size_type find_first_of(const char* cstr) const
size_type find_first_of(const char* cstr,size_type idx) const
size_type find_first_not_of(const char* cstr) const
size_type find_first_not_of(const char* cstr,size_type idx) const

size_rtpe find_first_of(char c) const
size_tyoe find_first_of(char c,size_type idx) const
size_type find_first_not_of(char c) const
size_type find_first_not_of(char c,size_type idx) const

查找最後一個符合條件的字符
size_type find_last_of(const String& str) const
size_type find_last_of(const String& str,size_type idx) const
size_type find_last_not_of(const String& str) const
size_type find_last_not_of(const String& str,size_type idx) const

size_type find_last_of(const char* cstr) const
size_type find_last_of(const char* cstr,size_type idx) const
size_type find_last_not_of(const char* cstr) const
size_type find_last_not_of(const char* cstr,size_type idx) const

size_rtpe find_last_of(char c) const
size_tyoe find_last_of(char c,size_type idx) const
size_type find_last_not_of(char c) const
size_type find_last_not_of(char c,size_type idx) const

- 字符串剪切

String substr() const
String substr(size_type idx) const
String substr(size_type idx,size_type len) const

- 數值轉換

int stoi(const String& str)
int stol(const String& str)
int stoul(const String& str)
int stoll(const String& str)
int stoull(const String& str)
int stof(const String& str)
int stod(const String& str)
int stold(const String& str)

String to_string(Type val)
```

C++標準庫（四）之String