Need help with error checking

Hello,

I'm trying to get my error handling code (conditions) to work for my code. Basically, what I'm trying to do is when a user to be greeted with an error message if enter a number other than 1 or 2, or if they enter a letter (a non numerical value).

disp('For the following questions, press 1 for yes and 2 for no')
check1 = input (' Does your projectile departure and landing zone share a similar height?: ');
check2 = input (' are you trying to clear a wall?: ');
check3 = input (' Is there an initial velocity?: ') ;

while check1(isnan) || check1~=1 && check1~=2
    check1(isnan)
    disp ('Error! Input a number (either 1 or 2') 
    elseif check1~=1 && check1~=2
        disp('Error! Only input 1 for yes and 2 for no')
end 
end 

Answer 1

[James Tursa]

There are various ways to code this, but keeping the same basic architecture you have chosen you could do this:

while( true )
    disp('For the following questions, press 1 for yes and 2 for no')
    check1 = input (' Does your projectile departure and landing zone share a similar height?: ');
    check2 = input (' are you trying to clear a wall?: ');
    check3 = input (' Is there an initial velocity?: ') ;
    if( (isequal(check1,1) || isequal(check1,2)) && ...
        (isequal(check2,1) || isequal(check2,2)) && ...
        (isequal(check3,1) || isequal(check3,2)) )
        break;
    end
    disp('Error! Only input 1 for yes and 2 for no')
end 

This will run in a loop until the checks pass.

[Farouk Omer]

The project requires us only to make use of if,while,else,elseif conditions conditions and for/while loops. Is there another way where it could be done that way (similar to the way I wrote it)? Thanks for the input.

[James Tursa]

My suggestion uses only the while and if controls. This seems to match your requirements.