c++ error declaring vector in header file

Question

can't find an answer to this anywhere. haven't used c++ for long. in this file, 512, 256, 4736, and 448 all red-underlined as error 'expecting type specifier'

// AttackSqrs.h
#include <valarray> 
#include <vector>
#include <unordered_map> 
#include <string> 
#include <iostream>

class AttackSqrs
{
public:
    AttackSqrs();
    ~AttackSqrs();

private:
    void init();
    std::valarray<int> board(512);
    std::valarray<int> vrChessPieces(256);
    std::valarray<int> vrAttackSqrs(4736);
    std::valarray<int> vrNumAttackSqrsEachSqr(448);
};

but when i create this header file:

// diag.h
#include <valarray> 
#include <vector>
#include <unordered_map> 
#include <string> 
#include <iostream>


    void init();
    std::valarray<int> board(512);
    std::valarray<int> vrChessPieces(256);
    std::valarray<int> vrAttackSqrs(4736);
    std::valarray<int> vrNumAttackSqrsEachSqr(448);

the errors go away. thanks in advance for any help.

You can't use parentheses for non-static data member initializers. — chris, Aug 05 '14 at 23:57
If you haven't any memory of C++, why not get a book and learn it systematically? Whar you wrote isn't valid syntax. — Kerrek SB, Aug 05 '14 at 23:58

score 1 · Answer 1 · answered Aug 05 '14 at 23:58

You don't initialize members that way. Use the initialization list of the AttackSqrs constructor:

class AttackSqrs
{
    public:
    AttackSqrs();
    ~AttackSqrs();

private:
    void init();
    std::valarray<int> board;
    std::valarray<int> vrChessPieces;
    std::valarray<int> vrAttackSqrs;
    std::valarray<int> vrNumAttackSqrsEachSqr;
};

// Then in a CPP file
AttackSqrs::AttackSqrs() :  board(512), vrChessPieces(256), vrAttackSqrs(4736), 
                 vrNumAttackSqrsEachSqr(448) {}

score 1 · Answer 2 · answered Aug 05 '14 at 23:59

1

On the header file, you only declare the variable and their types. Any kind of object construction is implemented in the cpp file.

AttackSqrs.h

class AttackSqrs
{
public:
    AttackSqrs();
    ~AttackSqrs();

private:
    void init();
    std::valarray<int> board;
    std::valarray<int> vrChessPieces;
    std::valarray<int> vrAttackSqrs;
    std::valarray<int> vrNumAttackSqrsEachSqr;
};

AttackSqrs.cpp

AttackSqrs::AttackSqrs() : 
        board(512), 
        vrChessPieces(256), 
        vrAttackSqrs(4736), 
        vrNumAttackSqrsEachSqr(448){

}

answered Aug 05 '14 at 23:59

B.R.W.

1,566
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C++11 allows for initializing members in the class definition. – chris Aug 06 '14 at 00:00
That's new to me. You refer to using more template arguments, like Neil Kirk answered? – B.R.W. Aug 06 '14 at 00:02
I believe there is new C++11 syntax to call constructor of members in class definition, but I'm not familiar with it. – Neil Kirk Aug 06 '14 at 00:04
1

@BrunoWerminghoff, It's as simple as `int m_i = 5;` to initialize `m_i` to 5 by default. You can use copy-initialization or list-initialization, but not direct-initialization. – chris Aug 06 '14 at 00:38

score 0 · Answer 3 · answered Aug 05 '14 at 23:58

Your question is about vectors but you use valarray, which I haven't used before. I will answer for vectors.

You need to set the size of the vectors in the constructor.

header file

class AttackSqrs
{
public:
    AttackSqrs();
    ~AttackSqrs();

private:
     std::vector<int> board(512);
};

cpp file

AttackSqrs::AttackSqrs()
: board(512)
{
}

Alternatively, as the sizes are constant, you can use arrays.

class AttackSqrs
{
public:
    AttackSqrs();
    ~AttackSqrs();

private:
    std::array<int, 512> board; // c++11
    int board[512]; // pre-c++11
};

c++ error declaring vector in header file

3 Answers3