file - What is wrong with this loop? FprintF in matlab -

i have loop supposed search through file , add text

fid = fopen('wave_propagation_var5_alpha1delta1.cps_001', 'rt+') fprintf(fid, 'dsadsado') =1:383              currentline = fgetl(fid)             currentline = strtrim(currentline)             if strcmp(currentline, '$$solid_anormal')==1                 fprintf(fid, 'hello')             elseif strcmp(currentline, '$$solid_deltanormal')==1                 fprintf(fid, num2str(deltalist(i)))             else             end     i=i+1 end 

line 2 appears print file correctly. cannot figure out why lines 7 , 9 won't. when debug if statement satisfied , code goes both lines , executes them. when open target file dont understand why nothing happening....

please help. thanks.

it bad idea try actively read , write same file in matlab. you'll instead want use different file output.

fin = fopen('wave_propagation_var5_alpha1delta1.cps_001', 'rt+'); fout = fopen('wave_propagation_var5_alpha1delta1.cps_001.out', 'w');  =1:383     currentline = fgetl(fin)     currentline = strtrim(currentline)     if strcmp(currentline, '$$solid_anormal')==1         fprintf(fout, 'hello')     elseif strcmp(currentline, '$$solid_deltanormal')==1         fprintf(fout, num2str(deltalist(i)))     end      % print newline every time correspondence     fprintf(fout, '\n')     i=i+1 end  fclose(fin) fclose(fout)  % replace input file output file if want movefile('wave_propagation_var5_alpha1delta1.cps_001.out', ...          'wave_propagation_var5_alpha1delta1.cps_001');