Thread: Assign Character Arrays data from an STL Container

One way you could do it is to dynamically allocate an array based on the size of the vector:

Code:

#include <iostream>
#include <vector>

using namespace std;

#define ARAY_MAX 4

int main()
{
    char chString[ARAY_MAX] = {'A', 'B', 'C', 'D'};
    char *pString;
    vector<char> vChar;

    for (int i = 0; i < ARAY_MAX; i++)
        vChar.push_back(chString[i]);

    pString = new char[vChar.size()];

    for (vector<char>::const_iterator iter  = vChar.begin();
         iter != vChar.end();
         ++iter)
    {
        static int siCount = 0;
        pString[siCount] = (*iter);
        ++siCount;
    } // end for loop

    for (i = 0; i < vChar.size(); i++)
        cout << pString[i] << " ";

    delete [] pString;

    return 0;
} // end main

David

If you just need to convert for file writing/reading then you can cast -

Code:

vector <int> vec;
	ofstream os("file.txt",ios::binary);
	vec.push_back(10);
	vec.push_back(5);

	for(vector <int>::iterator it=vec.begin();it!=vec.end();it++)
						os.write((char*)it,sizeof(int));

First, what does:

vChar.size();

return?

This returns a integer count of the total number of elements contained in the vector.

Lastly, you used:

++iter

Note the preincrement. In this particular code, it believe it is arbitrary. Am I correct?

Correct. It does not matter if it is pre or post. It is just habit for me to use the preincrement here.

David

What is the difference between:

(char*)

and

reinterpret_cast<char *>(it)?

They'll both do the same thing, but the second is exclusive to C++, wheres the first comes from C++'s C heritage. The different types of casting in C++ (static_cast, const_cast, etc) allow the compiler to do differing amounts of checking depending on the type of cast you want to do. For instance you might use const_cast to remove a const modifier but still want the compiler to do the normal type checking. AFAIK reinterpret_cast does virtually no type checking and is more or less equivilent to the C cast (and I'm lazy and can never be bothered to type the full C++ syntax for casting).