putting symbols center of board

[Ph0x]

I try to put 4 symbols on a user-sized board. Firstly, it works for `n x n` but when I want to convert `m x n` I can't get expected result. It works for some tryings but not for all. For example:
Original algorithm:

 
                table[center][center - 1] = p_symbol;
                table[center - 1][center] = p_symbol;
                table[center][center] = c_symbol;
                table[center - 1][center - 1] = c_symbol;

    Expected result:
    row = 4, col = 8
      abcdefgh
     1........
     2...xo...
     3...ox...
     4........
     Output result:
       abcdefgh
     1........
     2........
     3...xo...
     4...ox...
    
     Expected result:
    row = 12, col = 6
       abcdef
     1......
     2......
     3......
     4......
     5......
     6..xo..
     7..ox..
     8......
     9......
    10......
    11......
    12......
    Output result:
      abcdef
     1......
     2......
     3......
     4......
     5......
     6....xo
     7....ox
     8......
     9......
    10......
    11......
    12......

Code:

    #include <iostream>
    #include <iomanip>
    using namespace std;
    
    char const c_symbol = 'x';
    char const p_symbol = 'o';
    char const what_symbol = '.';
    
    void show(char const table[][100], short const row_size, short const col_size)
    {
        cout << endl << setw(3);
        for(short i = 0 ; i < col_size ; ++i)
            cout << static_cast<char>(i + 'a');
        cout << endl;
        
        for(short i = 0; i < row_size; ++i)
        {
            cout << setw(2) << i + 1;
            for(short j = 0; j < col_size; j++)
                cout << table[i][j];
            cout << endl;
        }
        cout << endl;
    }
    
    int main()
    {
        int row_size;
        int col_size;
        char table[100][100];
        
        cin >> row_size >> col_size;
        
        short center = 0;
        for(short i = 0; i < row_size; ++i)
            for(short j = 0; j < col_size; ++j)
            {
                table[i][j] = what_symbol;
            }
        if (row_size < col_size)
        {
            center = col_size / 2;
            if (col_size % 2 == 0)
            {
                table[center - 1][center - 1] = p_symbol;
                table[center - 2][center] = p_symbol;
                table[center - 1][center] = c_symbol;
                table[center - 2][center - 1] = c_symbol;
            }
            else
            {
                table[center][center - 1] = p_symbol;
                table[center - 1][center] = p_symbol;
                table[center][center] = c_symbol;
                table[center - 1][center - 1] = c_symbol;
            }
        }
        else
        {
            center = row_size / 2;
            if (row_size % 2 == 0)
            {
                table[center][center - 2] = p_symbol;
                table[center - 1][center - 1] = p_symbol;
                table[center][center - 1] = c_symbol;
                table[center - 1][center - 2] = c_symbol;
            }
            else
            {
                table[center][center - 1] = p_symbol;
                table[center - 1][center] = p_symbol;
                table[center][center] = c_symbol;
                table[center - 1][center - 1] = c_symbol;
            }
        }
        
        show(table, row_size, col_size);
        
        return 0;
    }

How can be the issue overcome? I have thought for hours but am stuck.