How to Implement Box Function in better way in Matlab?

Question

• This function in Matlab presents Box_Function:

  • output = 1 while sample n belongs to the range (-a, +a).
  • otherwise the output is 0 outside that range.

• So how can I implement this function in Matlab in a better way to shift the plot in case of negative values of time, without assigning negative values to the array.

Thanks in Advance

function B_X = Box_Func(N,K,a)
if(N <= 0)||(K+a > N) 
    warning('Please Enter Valid Positive Integer !');
else 
    B_X = zeros([-N N]); 
    for i = -N : 1 : N 
         if (i >= K-a) && (i <= K+a) 
            B_X(i)=1;
        end
    end
end
end

Answer 1

function B_X = Box_Func(N,K,a)
%   Box_Func This Function takes Number of Samples N,Count of shift K, and 
%   half of Box width a then it stem Them ,
%   Note it works only for positive shifting
%   that means K should be positive or Zero

if(N <= 0)||(K+a > N) % if samples Number wrong, or shifting exceeds limit
    % of Samples Print a warning.
    warning('Please Enter Valid Positive Integer !');
else % if The inputs are fine , then :
    B_X = zeros([1 2*N+1]);
    x = -N:N;
    B_X(x>=(K-a) & x<=(K+a)) = 1;
    end
%===========================================    
% Plotting the Results
%=========================================== 
    figure('Name','Box Function','NumberTitle','off');
    stem(x,B_X)
    hold on
    xlabel('Samples')
    ylabel('Box Shifeted Function')
    xlim([-N N]) ;
    ylim([-1 2]);
    grid on
    hold off
end