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operator< (<string>)

Tests if the string object on the left side of the operator is less than to the string object on the right side.

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 
   );

_Left

A C-style string or an object of type basic_string to be compared.

_Right

A C-style string or an object of type basic_string to be compared.

true if the string object on the left side of the operator is lexicographically less than the string object on the right side; otherwise false.

A lexicographical comparison between strings compares them character by character until:

  • It finds two corresponding characters unequal, and the result of their comparison is taken as the result of the comparison between the strings.

  • It finds no inequalities, but one string has more characters than the other, and the shorter string is considered less than the longer string.

  • It finds no inequalities and finds that the strings have the same number of characters, and so the strings are equal.

// 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;
}
The basic_string s1 = strict.
The basic_string s2 = strum.
The C-style string s3 = strict.
The string s1 is less than the string s2.
The string s1 is not less than the string s3.
The string s3 is less than the string s2.

Header: <string>

Namespace: std

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