c++ - Sorting a C-style array -

i'm stuck on 1 part of assignment. i'm not sure c-style array is. when sort normal array, sort function works. however, red squiggly in code try sort c-style array. there i'm doing wrong? appreciate help. in advance.

// goal: populate c-style array of 40 million elements random values between      //          1 , 4 billion , sort via sort() algorithm. note should use new      //          operator allocate array.      // note: array created/initialized with 40 million elements using new operator.      start_time = time(null); // record start time      {          size_t *a1 = new size_t[forty_million];          (int = 0; < forty_million; ++i)         {             a1[i] = randomint(engine);         }          sort(a1.begin(), a1.end());      }      end_time = time(null); // record end time     total_time = end_time - start_time; // calculate time compute     cout << "it took " << static_cast<long>(total_time) << " seconds compute part " << part++ << "\n" << endl; 

i not sure mean red squiggly line, guess is, ide highlights part of code indicating may not correct. based on question, best guess is, erroneous line is

sort(a1.begin(), a1.end()); 

and possibly because a1 not container. reasoning seconding on reference terminology c-style array.

c-style array non standard-library implementation of homogeneous collection of elements contiguous in memory.

such arrays not objects in pure terminology of object oriented, , not have methods (member functions in c++) , properties ( data members in c++).

naturally, may not able perform method call fetch start , end iterators, indicating begin , end of array.

fortunately there couple of way outs

1. if using c++11 , beyond, can leverage free standing functions std::begin , std::end instead of invoking member functions

   sort(std::begin(a1), std::end(a1)); 

2. if size of array know, can add array end of array.

   sort(a1, a1 + sizeof(a1)/sizeof(a1[0])); 

   or better

   template < typename ty, size_t n > size_t countof( ty ( & arr )[ n ] ) {      return n; }  ................. sort(a1, a1 + n);