C++ OOP Summary

The program's core objective is to solve the classic 8 Queens Problem, which involves placing eight chess queens on an $8 \times 8$ chessboard such that no two queens threaten each other. This means no two queens can share the same row, column, or diagonal.
The implementation represents an $8 \times 8$ chessboard visually, with each square being represented by a $5 \times 7$ 2D character array for detailed graphical output.
Black and white boxes (squares on the chessboard) are visually constructed using these $5 \times 7$ 2D character arrays, allowing for a structured and stylized representation of the board.

typedef is a C++ keyword that allows programmers to create a new name for an existing data type, effectively creating an alias.
Syntax: typedef existing_type new_type_name;
Application in this program: A typedef is used to define box as an alias for a char[5][7] data type. This simplifies code readability and maintenance by providing a clear, descriptive name for the complex 2D character array structure used to represent a single chessboard square.

The datatype box is defined as typedef char box[5][7]; where char[5][7] is a 2D array capable of storing characters for a $5 \times 7$ grid.
Two primary box instances are utilized: bb (black box) and wb (white box).
- Each element in bb contains the ASCII character (char)219 (a solid block character) to visually represent a black square.
- Each element in wb contains a space character to represent an empty white square.
The actual chessboard, board, is declared as a $8 \times 8$ 2D array of pointers to box type (e.g., box *board[8][8];). This design choice is critical for memory efficiency because instead of creating 64 individual box objects (each being $5 \times 7$ characters), only two box objects (bb and wb) are created.
Each element board[i][j] on the chessboard array stores the address of either the bb or wb box, depending on whether the square at position $(i, j)$ is black or white, respectively. This minimizes memory usage by pointing multiple board squares to the same two box character arrays.

The board is printed using a series of nested loops: two outer loops iterate through the $8 \times 8$ board squares ( $i$ for rows, $j$ for columns) and two inner loops iterate through the $5 \times 7$ dimensions of each box ( $k$ for box rows, $l$ for box columns).
Accessing box elements through pointers when printing: The expression cout << (*board[i][j])[k][l]; is used to print each character.
- board[i][j] retrieves the pointer to a box (either &bb or &wb) stored at the current board position.
- *board[i][j] dereferences this pointer, yielding the actual box char[5][7] array.
- [k][l] then accesses the specific character within that box at row $k$ and column $l$ .