operator< (<string>)

测试，如果运算符左侧的字符串对象小于对于右侧的字符串对象。

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 
   );

参数

• _Left
  用 . 式字符串或类型要比较的 basic_string 对象。

• _Right
  用 . 式字符串或类型要比较的 basic_string 对象。

返回值

true，如果运算符左侧的字符串对象与右侧的字符串字典对象是小于；为 false。

备注

在字符串之间存在着字典来比较字符由比较这些字符之前：

• 找到不相等两个相应的字符，并且，它们的比较结果采用作为比较在字符串之间。

• 它不以查找不相等，但字符串与其他具有多个字符，因此，较短的字符串大于较长的字符串被视为小。

• 它不查找不相等和查找字符串有字符数相同，并且，因此字符串相等。

示例

// 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;
}

要求

标头：< 字符串>

命名空间: std

请参见

参考

string::operator<