char_traits::to_int_type

將 char_type 轉換成字元對應的 int_type 字元並傳回結果。

static int_type to_int_type( 
   const char_type& _Ch 
);

參數

• _Ch
  以 int_type表示的 char_type 字元。

傳回值

與 char_type 字元對應的 int_type 字元。

備註

轉換作業 to_int_type 和 to_char_type 彼此相反的，因此，:

to_int_type ( to_char_type ) x== (x)

對於任何 int_type x，和

to_char_type ( to_int_type ) x== (x)

對於任何 char_type x。

範例

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

int main( ) 
{
   using namespace std;
   char_traits<char>::char_type ch1 = 'a';
   char_traits<char>::char_type ch2 = 'b';
   char_traits<char>::char_type ch3 = 'a';

   // Converting from char_type to int_type
   char_traits<char>::int_type int1, int2 , int3;
   int1 =char_traits<char>:: to_int_type ( ch1 );
   int2 =char_traits<char>:: to_int_type ( ch2 );
   int3 =char_traits<char>:: to_int_type ( ch3 );

   cout << "The char_types and corresponding int_types are:"
        << "\n    ch1 = " << ch1 << " corresponding to int1 = " 
        << int1 << "."
        << "\n    ch2 = " << ch2 << " corresponding to int1 = " 
        << int2 << "."
        << "\n    ch3 = " << ch3 << " corresponding to int1 = " 
        << int3 << "." << endl << endl;
   
   // Converting from int_type back to char_type
   char_traits<char>::char_type rec_ch1;
   rec_ch1 = char_traits<char>:: to_char_type ( int1);
   char_traits<char>::char_type rec_ch2;
   rec_ch2 = char_traits<char>:: to_char_type ( int2);

   cout << "The recovered char_types and corresponding int_types are:"
        << "\n    recovered ch1 = " << rec_ch1 << " from int1 = " 
        << int1 << "."
        << "\n    recovered ch2 = " << rec_ch2 << " from int2 = " 
        << int2 << "." << endl << endl;
   
   // Testing that the conversions are inverse operations
   bool b1 = char_traits<char>::eq ( rec_ch1 , ch1 );
   if ( b1 )
      cout << "The recovered char_type of ch1"
           << " is equal to the original ch1." << endl;
   else
      cout << "The recovered char_type of ch1"
           << " is not equal to the original ch1." << endl;

   // An equivalent and alternatively test procedure
   if ( rec_ch2 == ch2 )
      cout << "The recovered char_type of ch2"
           << " is equal to the original ch2." << endl;
   else
      cout << "The recovered char_type of ch2"
           << " is not equal to the original ch2." << endl;
}

需求

標頭：<string>

命名空間: std

請參閱

參考

char_traits 結構