Write Decimals to 12 Bit Signed Binary

I am trying to take a set of integer decimal inputs (ranging from -100 to 100) and map them to 12 bit signed binary. The trick is that the binary must consists of 12 bits, even if there are leading zeros. So far I have generated the integers, converted them to 16 (not 12) bit signed binary, but am really struggling with making all of the binary numbers 12 bits long.

For example, if the integer is 23, the binary should be 000000010111. If the integer is -23, the binary should be 111111101001. I then need to write these signed binary numbers to a text file with each binary number on a new line. So far I have what is below, but the output is 16 bit and there are no leading zeros. I have struggled for an answer but haven't found it. Any help is greatly appreciated!

 integers=round(200*(rand(1,8000)-0.5));

 for i=1:8000
    binary{i}=dec2bin(typecast(int16(integers(i)),'uint16'));
 end

Answer 1

[Walter Roberson]

temp = integers;
mask = temp < 0;
temp(mask) = 2^12 + temp(mask) ;
binary = dec2bin(temp, 12);

[Karl Haebler]

Hey Watler, thanks for the response. It seems to be working, but I can't seem to then write each line to a textfile. For example, using the below code prints everything in one line, and not each binary number on its own line. Do you know how I can properly print everything to it's own line? Thanks.

 filename='test2.txt';
 fileID=fopen(filename,'w');
 fprintf(fileID, '%s\n',binary);

[Karl Haebler]

Nevermind I figured it out! Thanks for the help

[Walter Roberson]

temp = cellstr(binary);
fprintf(fileID, '%s\n', temp{:});