I have a few if statements within a while statement, i want them to display different values based on input but they're being skipped over

The following code is a 'game' meant to simulate a ball being thrown at different angles. The ball needs to land on a platform and in turn wil give the player a point.

The two main issues i've had with it are:

• when "x" is the input it should display thanks for playing (or a similar message)
• when an angle less than -90 deg and greater than 90 deg is the input it should say invalid input

(here is my code)

%script file
h=figure;
clf(h);
AxesH = axes('NextPlot','add');
disp('Press x to exit')
kwhile = 1;
x = NaN(1);
while theta ~= x
    theta = input('Please input angle: ');
    
    if theta >= -90 && theta <= 90
        
        [xf,yf] = HDTask1function_f(theta);
        
        z = rand()*3.5;
        pts = 0;
        j = z+0.5;
        
        hndl2=plot([z j],[0 0],'LineWidth',5);
        
        hold on
        
        set(gca,'Xlim',[-1 4])
        
        set(gca,'Ylim',[-1 4])
        
        hndl=plot(xf(1),yf(1),'r.','MarkerSize',50);
        
        hold off
        for ii=2:length(xf)
            
            drawnow;
            pause(0.02)
            set(hndl,'XData', xf(ii), 'YData', yf(ii));
            
            pause(0.0025);
            
            if yf(ii:end) < 0
                
                yf(ii:end) = 0;
                
                pause(0.5);
                
                if xf(1,ii) > z && xf(1,ii) < j
                    pts = pts + 1;
                    disp('You gained a point');
                    
                    hold off
                    
                    
                end
                
                break
                
            end
            
        end
        
    elseif theta == x
        kwhile = kwhile - 1;
        disp('Closing Game...')
        break
        
    else
        disp('<3 Try again. That''s not a valid angle')
        continue
        
        
    end
    
end   %end of while loop
disp('Thanks for Playing')

I've read through a few different online examples but haven't had much luck.

Any help is appreciated, i've been working on this problem all day and my brain is turning into jelly.

[dpb]

kwhile = 1;
x = NaN(1);
while theta ~= x
  ...

theta is uniinitialized...

Rearrange the test on theta to reject the unallowed first and then can get rid of all the other else, etc., ...

You're test a variable x instead of a character string 'X'. You'll need to be case-insensitive there, too...

Answer 1

[Alan Moses]

Hi Joshua, from your code I understand that you want to type the letter ‘x’ to close the game and display “Thanks for Playing”. To do so, add the following lines of code instead of “x=NaN(1)”:

x = 'x';
theta = 0;

This ensures the variable ‘theta’ is initialized before entering the loop, and terminates the code on entering the letter ‘x’.