Can this code be more efficient?

I wrote this code with some help of a classmate and I think the code can run more efficiently. It coverts whole numbers & numbers between 0 & 1 to binary numbers. Any help is appreciated.

n=input('Enter a positive value: ');
i=n; j=1; k=1; stop=0; binary=0; binaryStr='0';
if n>=1 || n==0
% i=n; j=1;
% binary=0;
% binaryStr='0';
while i>=1
  binary(j)=rem(i,2);
  i=floor(i/2);
  j=j+1;
end
  %disp(binary);
  binary=fliplr(binary);
%converting the binary vector to type string:
for k=1:length(binary)
  binaryStr(k)=num2str(binary(k));
end
% disp(binaryStr);
elseif n>0 & n<1;
while i~=1
  if stop==1
     break; %break the main while-loop
  end
  i=i-floor(i); %subtracts the lead integer, 1 or 0, from the decimal.
  value(j)=i;
  while j>=2 && k<j %a loop that compares i to all previous values of i
      if value(k)==value(j)
          stop=1; %a value to break the main loop.
          break %breaks this inner while-loop
      end
      k=k+1;
  end %end of comparison loop
  i=i*2;
  binary(j)=floor(i);
  j=j+1;
  k=1;    
end
for k=1:length(binary)
  binaryStr(k)=num2str(binary(k));
end
binaryStr=strcat('.',binaryStr); %adds '.' to the front of binaryStr
end
disp(binaryStr);

Answer 1

[Walter Roberson]

For one thing you should look at dec2bin()

[David Hughes]

The purpose of the code is to not use built in matlab functions.

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/38787-what-can-be-programmed-without-any-built-in-functions