I'm trying to create a random sequence of 100 DNA bases, with an equal number of A,C,G and T, but I can't make it happen.

I'm trying to create a random sequence of 100 DNA bases, with an equal number of A,C,G and T, but I can't make it happen. My code is:

total_bp=10000;

%open file
fid=fopen('Seq_Out.txt','w');

for i=1:total_bp
%random DNA sequence
SeqLength=100;
Seq=randseq(SeqLength,'Weights',[0.25 0.25 0.25 0.25]);

%write to file
fprintf(fid,'%s\n',Seq);
end

fclose('all');