How can i correctly write an if "yes or no" statement?

For Example, x=input('Do you know the area of your building?(yes/no)' ,'s') if (x=='yes') area=input('What is the area of your building?') elseif (x=='no') shape=input('is your building circular or rectangular?') end How could i make it so that if the input is "yes" or "no" that it would do one of the following commands?

Answer 1

[Jan]

if strcmpi(x, 'yes')
  ...
elseif strcmpi(x, 'no')
  ...
else
  error('Please type "yes" or "no"');
end

The == is the elementwise comparison, which fails when x and 'yes' have a different number of characters.

Answer 2

[Salam Ismaeel]

Just for genral use, not necessary for this case only. I create this function:

%******************************************************************************************
% CheckYesOrNo.m 
% This function return 1 for Yes and 0 for No
% Input 
%           chos : charater variable 
% Output:
%          T : Logic variable (0 or 1)
%******************************************************************************************

function T = CheckYesOrNo(chos)

chos = lower(chos);
while chos ~= 'y' || chos ~= 'n'
    if chos == 'y' || chos == 'n'
        break
    else
        chos=input('Please input y or n? ','s');
    end
end
if chos =='y'
    T = 1;
else
    T = 0;
end