% The ?target? game
% Author: F. P. Schloerb

% set parameters for calculation
g = 9.8; %grav. acceleration
v0 = 100; %initial velocity
tolerance = 0.1; % tolerance for a hit

% randomly select the target distance.
rand('state',sum(100*clock)); % seeds random number
etrue = rand()*pi/2;
dtrue = cannon_ball_distance(etrue, g, v0);

% challenge the player
fprintf('Select cannon elevation to hit the target!\n');
fprintf('NOTE: g=%3.1f m/s/s; v= %6.1f m/s\n',g,v0);
fprintf('The target distance is: %f m\n',dtrue);

% now prompt the player for guesses
KeepTrying = true;
while (KeepTrying)
    e = input('Enter Elevation Angle (deg.): ');
    e = e*pi/180; %convert to radians
    d = cannon_ball_distance(e, g, v0);
    if (abs(d-dtrue)<tolerance)
        e = e/pi*180; %convert to degrees
        fprintf('HIT! elevation=%f distance= %f\n',e,d);
        KeepTrying = false;
    else
        fprintf('MISS! (error = %f )\n',d-dtrue);
    end
end