operator< (<string>)

測試，如果在運算子左方的字串物件小於至右邊的字串物件。

template<class CharType, class Traits, class Allocator> 
   bool operator<( 
      const basic_string<CharType, Traits, Allocator>& _Left, 
      const basic_string<CharType, Traits, Allocator>& _Right 
   ); 
template<class CharType, class Traits, class Allocator> 
   bool operator<( 
      const basic_string<CharType, Traits, Allocator>& _Left, 
      const CharType *_Right 
   ); 
template<class CharType, class Traits, class Allocator> 
   bool operator<( 
      const CharType *_Left, 
      const basic_string<CharType, Traits, Allocator>& _Right 
   );

參數

• _Left
  C. 式字串或型別要比較的 basic_string 物件。

• _Right
  C. 式字串或型別要比較的 basic_string 物件。

傳回值

true ，如果在運算子左方的字串物件動詞命令一般地小於右邊的字串物件;否則 false。

備註

在字串之間的比較字元所比較字元直到:

• 找到兩個對應的字元視為不相同，因此，其比較的結果會因為比較的字串。

• 它不會尋找不等比較，不過，一串比其他有多個字元，因此，較短的字串會視為小於較長的字串。

• 它不會出現在發現字串的字元數，和，因此字串相等。

範例

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

int main( )
{
   using namespace std;
   // Declaring an objects of type basic_string<char>
   string s1 ( "strict" );
   string s2 ( "strum" );
   cout << "The basic_string s1 = " << s1 << "." << endl;
   cout << "The basic_string s2 = " << s2 << "." << endl;

   // Declaring a C-style string
   char *s3 = "strict";
   cout << "The C-style string s3 = " << s3 << "." << endl;

   // First member function: comparison between left-side object
   // of type basic_string & right-side object of type basic_string
   if ( s1 < s2 )
      cout << "The string s1 is less than the string s2." << endl;
   else
      cout << "The string s1 is not less than the string s2." << endl;

   // Second member function: comparison between left-hand object
   // of type basic_string & right-hand object of C-syle string type
   if ( s1 < s3 )
      cout << "The string s1 is less than the string s3." << endl;
   else
      cout << "The string s1 is not less than the string s3." << endl;

   // Third member function: comparison between left-hand object
   // of C-syle string type & right-hand object of type basic_string
   if ( s3 < s2 )
      cout << "The string s3 is less than the string s2." << endl;
   else
      cout << "The string s3 is not less than the string s2." << endl;
}

需求

標頭：<string>

命名空間: std

請參閱

參考

string::operator<