直接上代码：
 
fid=fopen('C:\Users\yunsu\Desktop\test.txt','r');   
 i=1;
 while ~feof(fid)
     line=fgetl(fid);
     str{i}=line;
     i=i+1;
 end
 fclose(fid);
 str_char=char(str);
 str_order=sortrows(str_char);
 fid=fopen('C:\Users\yunsu\Desktop\test_order.txt','wt');
 [m,n]=size(str_order);
 for i=1:m
     fprintf(fid,'%s\n',str_order(i,:));
 end
 fclose(fid);