Initializing a vector from arrays going wrong

Question

I'm creating a vector<vector<char>> from char arrays as follows:

typedef vector<vector<char>> board;
...
char row0[] = {'X', '-', '-', '-', '-', '-', '-', '-', '-', 'X'};
char row1[] = {'-', 'X', '-', '-', '-', '-', '-', '-', 'X', '-'};
char row2[] = {'-', '-', 'X', '-', '-', '-', '-', 'X', '-', '-'};
char row3[] = {'-', '-', '-', 'X', '-', '-', 'X', '-', '-', '-'};
char row4[] = {'-', '-', '-', '-', 'X', 'X', '-', '-', '-', '-'};
char row5[] = {'-', '-', '-', '-', 'X', 'X', '-', '-', '-', '-'};
char row6[] = {'-', '-', '-', 'X', '-', '-', 'X', '-', '-', '-'};
char row7[] = {'-', '-', 'X', '-', '-', '-', '-', 'X', '-', '-'};
char row8[] = {'-', 'X', '-', '-', '-', '-', '-', '-', 'X', '-'};
char row9[] = {'X', '-', '-', '-', '-', '-', '-', '-', '-', 'X'};

vector<char> v0(row0[0], row0[9]);
vector<char> v1(row1[0], row1[9]);
vector<char> v2(row2[0], row2[9]);
vector<char> v3(row3[0], row3[9]);
vector<char> v4(row4[0], row4[9]);
vector<char> v5(row5[0], row5[9]);
vector<char> v6(row6[0], row6[9]);
vector<char> v7(row7[0], row7[9]);
vector<char> v8(row8[0], row8[9]);
vector<char> v9(row9[0], row9[9]);

board test;
test.push_back(v0);
test.push_back(v1);
test.push_back(v2);
test.push_back(v3);
test.push_back(v4);
test.push_back(v5);
test.push_back(v6);
test.push_back(v7);
test.push_back(v8);
test.push_back(v9);

Having done so, I expected to see the printed board looking like the original char arrays. However, it's printing like this:

X X X X X X X X X X
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
- - - - - - - - - -
X X X X X X X X X X 

Where am I going wrong?

EDIT: Here's how I'm printing the board:

    void printBoard(Board b){
    for (int r = 0; r <10; r++){
    cout << "\n";
        for (int c = 0; c <10; c++){
        cout <<  b[r][c] << " ";
        }
}

Answer 1

Your indices are wrong. The end iterator is supposed to point to one past the end of the array (and it is supposed to be a pointer, not a value as you have it currently). Using std::begin and std::end will make sure you don't get this wrong.

#include <vector>
#include <iostream>
#include <iterator>

using namespace std;

typedef vector<vector<char>> board;

void print_board(const board& b)
{
    for(const auto& inner : b) {
        for(auto c : inner) {
            std::cout << c << " ";
        }
        std::cout << "\n";
    }
}

int main() 
{
    char row0[] = {'X', '-', '-', '-', '-', '-', '-', '-', '-', 'X'};
    char row1[] = {'-', 'X', '-', '-', '-', '-', '-', '-', 'X', '-'};
    char row2[] = {'-', '-', 'X', '-', '-', '-', '-', 'X', '-', '-'};
    char row3[] = {'-', '-', '-', 'X', '-', '-', 'X', '-', '-', '-'};
    char row4[] = {'-', '-', '-', '-', 'X', 'X', '-', '-', '-', '-'};
    char row5[] = {'-', '-', '-', '-', 'X', 'X', '-', '-', '-', '-'};
    char row6[] = {'-', '-', '-', 'X', '-', '-', 'X', '-', '-', '-'};
    char row7[] = {'-', '-', 'X', '-', '-', '-', '-', 'X', '-', '-'};
    char row8[] = {'-', 'X', '-', '-', '-', '-', '-', '-', 'X', '-'};
    char row9[] = {'X', '-', '-', '-', '-', '-', '-', '-', '-', 'X'};

    vector<char> v0(std::begin(row0), std::end(row0));
    vector<char> v1(std::begin(row1), std::end(row1));
    vector<char> v2(std::begin(row2), std::end(row2));
    vector<char> v3(std::begin(row3), std::end(row3));
    vector<char> v4(std::begin(row4), std::end(row4));
    vector<char> v5(std::begin(row5), std::end(row5));
    vector<char> v6(std::begin(row6), std::end(row6));
    vector<char> v7(std::begin(row7), std::end(row7));
    vector<char> v8(std::begin(row8), std::end(row8));
    vector<char> v9(std::begin(row9), std::end(row9));

    board test;
    test.push_back(v0);
    test.push_back(v1);
    test.push_back(v2);
    test.push_back(v3);
    test.push_back(v4);
    test.push_back(v5);
    test.push_back(v6);
    test.push_back(v7);
    test.push_back(v8);
    test.push_back(v9);

    print_board(test);
}

Of course, you could (and should) construct this in place with C++11 using initializer lists - it'll save a lot of boilerplate code.

Answer 2

There are a few ways to pushing the data into the vectors. The first, and IMHO the best way, is to use the C++11 uniform initialization:

std::vector<char> v0 = {'X', '-', '-', '-', '-', '-', '-', '-', '-', 'X'};
// etc.

The second way is also using another C++11 feature: std::begin and std::end:

std::vector<char> v0(std::begin(row0), std::end(row0));

A third way, and the way to handle "iterators" of arrays before C++11 is to use pointers to the array:

std::vector<char> v0(static_cast<char*>(row0), static_cast<char*>(row0 + 10));

Note that I added 10 to the end, this is because the last iterator is actually one beyond the last entry.

---

By the way, if you have uniform location, you can initialize the board that way too:

board test = { v0, v2, /* etc... */ };

Answer 3

To initialize a vector from array you should write something like:

vector<char> v0(row0, row0 + 10);

As opposed to what you have done. I am surprised this code even compiles. Probably you should play a bit with compiler options to print more warnings.