This program solves the well known problem of the eight queens on a board. The problem is placing eight chess queens on the chessboard in a way that no queen can attack any of the other queens... in other words there must be no two queens on the same row, the same coloumn or the same diagonal.

The program generates the list of all possible solutions in which every solution is represented by an 8-digit numbers where every digit is between 1 and 8. The n-th digit tells on what columns should be placed the queen on the n-th row.

This program is a computer player of the classical tic-tac-toe. The program starts by visualizing a 9 squares board using the digits from 1 to 9 and asking to the human player what his/her move is and then replying to every move automatically. Replying '0' as the first move is assumed as the will of having the computer make the first move.

This program accepts in input an expression with numbers, the four basic operations (with parenthesis) ending with the special character ";" and prints out what the result of the computation is. For example giving as input the expression "((1*16+9)*16+6)*16+6;" the programm will reply "6502". NOTE: The eventuality of a division by zero has not been handled in this program.