C++ comparing bunch of values with a given one

Question

I need to compare one given value with a retrieved values. I do this several times in the code. I am not satisfied with how it looks and I am seeking for a some sort of an util

Answer 1

You don't need a std::set or a std::vector. Just use std::set_intersection()...

Code is best...

#include 
#include 
#include 
using namespace std;

#define COUNT(TYPE,ARRAY)  ( sizeof(ARRAY) / sizeof(TYPE) )

inline bool CaseInsensitiveCompare (const char * a, const char * b)
  {  return strcasecmp( a, b ) < 0;  }

int  main()
{
  const char * setA[] = { "the", "world", "is", "flat" };
  const char * setB[] = { "the", "empty", "set", "is", "boring" };

  stable_sort( setA,  setA + COUNT( const char *, setA ),
               CaseInsensitiveCompare );

  stable_sort( setB,  setB + COUNT( const char *, setB ),
               CaseInsensitiveCompare );

  cout << "Intersection of sets:  ";
  set_intersection( setA, setA + COUNT( const char *, setA ),
                    setB, setB + COUNT( const char *, setB ),
                    ostream_iterator(cout, " "),
                    CaseInsensitiveCompare );
  cout << endl << endl;
}

---

Or perhaps, given your 1-N lookup problem:
(Note: Use binary_search() AFTER sorting!)

if ( binary_search( setA, setA + COUNT( const char *, setA ),
            "is", CaseInsensitiveCompare ) )
  ...

if ( binary_search( setA, setA + COUNT( const char *, setA ),
            "set", CaseInsensitiveCompare ) )
  ...