CODEWITHSUNDEEP
c++vector
tmighty
tmighty

Reputation: 11389

C++: Get value from a vector

I have a function that I pass a pointer to a vector of unsigned char.

Can somebody please tell me how to get one of the values inside the function?

double CApp::GetCost(unsigned char *uBytes)
{
   unsigned char iHP;
   iHP=uBytes[49]; //this does not work
}

Edit: Sorry, I first thought that I should simplify my code, but I think too much can go wrong. Now here is the real declaration:

// ---------------------------------------
struct ByteFeature
{
    unsigned char Features[52];
};

class clsByteFeatures : public CBaseStructure
{
private:
   vector<ByteFeature> m_content;

protected:
   virtual void ProcessTxtLine(string line);

public:
   vector<ByteFeature> &Content();
   void Add(ByteFeature &bf);
};

vector<ByteFeature> &clsByteFeatures::Content()
{
   return m_content;
}

And this is how I use it:

dblTargetCost  = GetCost(m_ByteFeatures.Content()[iUnitID].Features);

Another question: Would it be bad to simply pass the vector like this?

double CApp::GetCost(vector<unsigned char> &uBytes)
{
  //...
}

Upvotes: 2

Views: 2723

Answers (1)

billz
billz

Reputation: 45410

Would it be bad to simply pass the vector like this?
double CApp::GetCost(vector<unsigned char> &uBytes)

Not it's the better way to pass it by reference. however you may want to add const qualifier if you don't want uBytes to be modified.

double CApp::GetCost(const vector<unsigned char> &uBytes)
{
   try
   {
     unsigned char iHP = uBytes.at(49);
     //... 
   }
   catch(std::exception& e)
   {
     // process e
   }
   //...
}

EDIT:

After you new post, I feel you only need to return a reference to the element of m_content then pass the reference to GetCost function

ByteFeature& clsByteFeatures::operator[](int i) { return m_content.at(i); }


double GetCost(const ByteFeature& bf)
{
    std::cout << bf.Features[49]; << std::endl;
    return 0.0;
}

then you call:

GetCost(m_ByteFeatures[iUnitID]);

Upvotes: 4

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