Make graph plot wait until error checking is done

 if disc >= 0
   disp(['This Quadratic equation has two roots']);
   disp(['the value of the roots are: ', num2str(x1) ' and ' num2str(x2)]);

   if x1 > x2

     while Start > x2
     disp(['The Start value must be less than: ', num2str(x2)]);
     Start = input('Please, input a Start value of x: ')
     end

     while End < x1
     disp(['The End value must be greater than: ', num2str(x1)]);
     End = input('Please, input an End value of x: ')
     end

   elseif x2 >x1
     while Start > x1
     disp(['The Start value must be less than: ', num2str(x1)]);
     Start = input('Please, input a Start value of x: ')
     end

     while End < x2
     disp(['The End value must be greater than: ', num2str(x2)]);
     End = input('Please, input an End value of x: ')
     end

   end

              ^
              |
This bit is includes the plot axis etc.
              |
              v
end

How do i get the plot to wait until the first section is done??

[jake harris]

This is the full code