转换std :: vector <T> 给char *

Question

I'm trying convert vector to char * for send by socket the type of T is a simple struct

struct CategoryStruct {
    int ID;
    char name[32];
};

std::vector<CategoryStruct> categories;

Function, where I'm trying to convert -

char * Category::decodeCategoryToCharArray()
{
    int structSize = sizeof(CategoryStruct),
        currentByte = 0,
        i = 0;

    if(decoded)
        delete [] decoded;

    decoded = new char[structSize * categories.size()];
    std::vector<CategoryStruct>::iterator start, end;

    start = categories.begin();
    end = categories.end();

    for(; start != end; start++, i++)
    {
        memcpy(decoded+currentByte, &categories[i], structSize);
        currentByte += structSize+1;
    }

    return decoded;
}

End return will be ""

Answer 1

There's no need for conversion , std::vector<CategoryStruct> already stores the data in a contigous memory area. so your function could be boiled down to

std::vector<CategoryStruct> categories;
char * Category::decodeCategoryToCharArray()
{
    return reinterpret_cast<char*>(categories.data());
}