MATLAB: How to convert num2str for fprintf(fid, )

Question

at the first i convert my string to number

x(indexi,indexj)=str2num(string);
               indexj=indexj+1  ;

but at the end i want to use fprintf and convert num to string num2str again to print it in text file

fprintf (fid ,       )

Answer 1

'%f' or '%g' or '%e'