C++: check if vector<Class> is subset of vector<Class> -

i have following piece of code. have 2 strings (k1, k2), break tokens using whitespace delimeter (t1, t2). want check if t1 contained in t2. problem issubset(t1, t1) 0 value returned. want avoid using vector<string> instead of vector<stringref>, if possible. doing wrong? output should 2 1's 2 0's instead.

#include<string> #include<iostream> #include <time.h> #include <string.h> #include <vector> #include <algorithm>  using namespace std;  class stringref {     private:         char const*     begin_;         int             size_;      public:         int size() const { return size_; }         char const* begin() const { return begin_; }         char const* end() const { return begin_ + size_; }          std::string tostring() {              std::string value(begin_);              return value;         }          stringref( char const* const begin, int const size )             : begin_( begin )             , size_( size )         {}          bool operator<(const stringref& s) const         {             return (strcmp(begin(), s.begin()) < 0);         } };   /************************************************  * checks if vector b subset of vector    *  ************************************************/ bool issubset(std::vector<stringref> a, std::vector<stringref> b) {     std::sort(a.begin(), a.end());     std::sort(b.begin(), b.end());     return std::includes(a.begin(), a.end(), b.begin(), b.end()); }   /************************************************  * split string using delimeter; returns vector *  ************************************************/ vector<stringref> split3( string const& str, char delimiter = ' ' ) {     vector<stringref>   result;      enum state { inspace, intoken };      state state = inspace;     char const*     ptokenbegin = 0;    // init satisfy compiler.     for( auto = str.begin(); != str.end(); ++it )     {         state const newstate = (*it == delimiter? inspace : intoken);         if( newstate != state )         {             switch( newstate )             {             case inspace:                 result.push_back( stringref( ptokenbegin, &*it - ptokenbegin ) );                 break;             case intoken:                 ptokenbegin = &*it;             }         }         state = newstate;     }     if( state == intoken )     {         result.push_back( stringref( ptokenbegin, &str.back() - ptokenbegin ) );     }     return result; }  int main() {      string k1 = "9 10";     string k2 = "9 10 2 3";     vector<stringref> t1 = split3(k1,' ');     vector<stringref> t2 = split3(k2,' ');      cout<<issubset(t1,t1)<<endl;     cout<<issubset(t2,t1)<<endl;     return 0; } 

edit: ------ corrections -------

changed tostring to:

std::string tostring() const {     std::string value(begin_, size_);     return value; } 

changed operator< to: (thanks @mike seymour)

bool operator<(const stringref& s) const {     return (std::lexicographical_compare(begin(), end(), s.begin(), s.end())); } 

finally, in split3, changed if block before return statement to:

if( state == intoken ) {     result.push_back( stringref( ptokenbegin, &str.back() + 1 - ptokenbegin ) ); } 

there issues in code.

result.push_back( stringref( ptokenbegin, &str.back() - ptokenbegin ) ); 

contains off-by-one error, size of last token short.

return (strcmp(begin(), s.begin()) < 0); 

and

std::string value(begin_); 

rely on \0 terminated c strings, not using \0 terminated c strings.

std::string tostring() { 

should const method.

after resolved of these issue, code worked.