CODEWITHSUNDEEP
c++c++11stdvectorvisual-c++-6
Mehdi Tanhatalab
Mehdi Tanhatalab

Reputation: 55

error in array sorting using vectors in VC++6 while no error in VC++2012

I used this line code in VC++2012 to sort integrated row array called arrayCosts. This code work in this version but d not work at VC++6 version.

vector< vector<float> > my_vector ;
for( const auto& row : arrayCosts ) my_vector.push_back( vector<float>( begin(row), end(row) ) ) ;
        sort( begin(my_vector), end(my_vector),
                    []( const vector<float>& a, const vector<float>& b ) { return a[1] < b[1] ; } ) ;

The errors in VC++6 is as following.

e:\logistics\projects\10\10\source1.cpp(190) : error C2143: syntax error : missing ',' before ':'
e:\logistics\projects\10\10\source1.cpp(190) : error C2530: 'row' : references must be initialized
e:\logistics\projects\10\10\source1.cpp(190) : error C2059: syntax error : ':'
e:\logistics\projects\10\10\source1.cpp(191) : error C2065: 'begin' : undeclared identifier
e:\logistics\projects\10\10\source1.cpp(191) : error C2065: 'end' : undeclared identifier
e:\logistics\projects\10\10\source1.cpp(192) : error C2059: syntax error : '['
e:\logistics\projects\10\10\source1.cpp(192) : error C2143: syntax error : missing ')' before '{'
e:\logistics\projects\10\10\source1.cpp(192) : error C2143: syntax error : missing ';' before '{'
e:\logistics\projects\10\10\source1.cpp(192) : error C2065: 'a' : undeclared identifier
e:\logistics\projects\10\10\source1.cpp(192) : error C2109: subscript requires array or pointer type
e:\logistics\projects\10\10\source1.cpp(192) : error C2065: 'b' : undeclared identifier
e:\logistics\projects\10\10\source1.cpp(192) : error C2109: subscript requires array or pointer type

Upvotes: 1

Views: 232

Answers (1)

Mike Seymour
Mike Seymour

Reputation: 254681

You're trying to use language features from 2011 with a compiler from 1997. That's not going to work.

You might have more success if you stick to C++98; although since your compiler predates even that, there's no guarantee that this would work.

// Define a comparison functor, to replace the lambda.
// This must be defined outside a function, for arcane reasons.
struct comparator {
    bool operator()(const vector<float>& a, const vector<float>& b) {
        return a[1] < b[1];
    }
};

vector< vector<float> > my_vector ;

// Use an old-school for loop; range-based loops didn't exist back then,
// and neither did "auto" type deduction.
// (This assumes arrayCosts is also a vector<vector<float>>; 
// change the iterator type if it's something else).
for (vector< vector<float> >::const_iterator it = arrayCosts.begin();
     it != arrayCosts.end(); ++it)
{
    // std::begin and std::end didn't exist either
    my_vector.push_back( vector<float>( it->begin(), it->end() ) ) ;
}

// Again, no std::begin or std::end.
sort(my_vector.begin(), my_vector.end(), comparator());

Upvotes: 4

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