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.
