basic_string::basic_string

發行項
06/09/2015

建構是空的，初始化由特定字元的字串，或者是另一個字串或物件 C 樣式 (以 null 終止) 字串的全部或部分複製。

basic_string();
explicit basic_string(
    const allocator_type& _Al
);
basic_string(
    const basic_string& _Right
);
basic_string(
    basic_string&& _Right
);
basic_string(
    const basic_string& _Right, 
    size_type _Roff,
    size_type _Count = npos
);
basic_string(
    const basic_string& _Right, 
    size_type _Roff,
    size_type _Count, 
    const allocator_type& _Al
);
basic_string(
    const value_type *_Ptr, 
    size_type _Count
);
basic_string(
    const value_type *_Ptr, 
    size_type _Count,
    const allocator_type& _Al
);
basic_string(
    const value_type *_Ptr
);
basic_string(
    const value_type *_Ptr,
    const allocator_type& _Al
);
basic_string(
    size_type _Count, 
    value_type _Ch
);
basic_string(
    size_type _Count, 
    value_type _Ch,
    const allocator_type& _Al
);
template <class InputIterator>
    basic_string(
        InputIterator _First, 
        InputIterator _Last
    );
template <class InputIterator>
    basic_string(
        InputIterator _First, 
        InputIterator _Last, 
        const allocator_type& _Al
    );
basic_string(
   const_pointer _First,
   const_pointer _Last
);
basic_string(
   const_iterator _First,
   const_iterator _Last
);

參數

_Ptr
表示使用初始化建構之 string 的 C 字串。這個值不可以是 null 指標。
_Al
建構的字串物件的儲存體配置器類別。
_Count
要初始化的字元數。
_Right
初始化字串的字串建構。
_Roff
一個字元的索引是之第一個初始化建構字串的字元值的字串。
_Ch
要複製的字元值至正在建構的字串。
_First
輸入 Iterator，解決 const_pointer 或的 const_iterator 要在中插入的來源範圍的第一個項目。
_Last
輸入 Iterator，解決 const_pointer 或的 const_iterator 位置於最後項目以外的來源範圍插入。

傳回值

由建構函式所建構的字串物件的參考。

備註

所有建構函式將 basic_string::allocator_type 並初始化受控制序列。若有配置器物件引數為 al。如需複製建構函式，它是 right.basic_string::get_allocator()。否則，它就是 Alloc()。

受控制序列初始化剩餘運算元指定的運算元序列的複本。沒有運算元序列的建構函式中指定一個空的初始控制順序。如果 InputIterator 是在範本中建構函式的整數型別，運算元序列 _First, _Last 一般作業與 (size_type)_First, (value_type)_Last相同。

範例

// basic_string_ctor.cpp
// compile with: /EHsc
#include <string>
#include <iostream>

int main( )
{
   using namespace std;

   // The first member function initializing with a C-string
   const char *cstr1a = "Hello Out There.";
   basic_string <char> str1a ( cstr1a , 5);
   cout << "The string initialized by C-string cstr1a is: "
        << str1a << "." << endl;

   // The second member function initializing with a string
   string  str2a ( "How Do You Do?" );
   basic_string <char> str2b ( str2a , 7 , 7 );
   cout << "The string initialized by part of the string cstr2a is: "
        << str2b << "." << endl;

   // The third member function initializing a string
   // with a number of characters of a specific value
   basic_string <char> str3a ( 5, '9' );
   cout << "The string initialized by five number 9s is: "
        << str3a << endl;

   // The fourth member function creates an empty string
   // and string with a specified allocator
   basic_string <char> str4a;
   string str4b;
   basic_string <char> str4c ( str4b.get_allocator( ) );
   if (str4c.empty ( ) )
      cout << "The string str4c is empty." << endl;
   else
      cout << "The string str4c is not empty." << endl;

   // The fifth member function initializes a string from
   // another range of characters
   string str5a ( "Hello World" );
   basic_string <char> str5b ( str5a.begin ( ) + 5 , str5a.end ( ) );
   cout << "The string initialized by another range is: "
        << str5b << "." << endl;
}

Output

The string initialized by C-string cstr1a is: Hello.
The string initialized by part of the string cstr2a is: You Do?.
The string initialized by five number 9s is: 99999
The string str4c is empty.
The string initialized by another range is:  World.