How to modify few numbers in a random text file?

I am uploading a text file related to a model in an electronic simulator. How to modify the 4 parameters named with

toxe = %1.1d
toxp = %1.1d
toxm = %1.1d
vth0 = %1.1d

If this text file didn't have format specifier, I would just write this file using

model = fileread(fullfile(pathname_model,filename_model));
File_model = fopen(fullfile(dirname,filename_model),'w');   
fprintf(File_model,'%s',model);
fclose(File_model);

Since now I want to modify a few parameters each time I run my code, I edited the text file and put format specifier but I don't know how can I print the modified file now.

Is this correct?

model = fileread(fullfile(pathname_model,filename_model));
File_model = fopen(fullfile(dirname,filename_model),'w');   
fprintf(File_model,'%s',model, par1, par2, par3, par4);
fclose(File_model);  

where par1 to par4 are the first 4 parameter values that I listed at the top.

Answer 1

[per isakson]

Try this

%%
chr = fileread('model_v2.txt');
ffs = 'model_out.txt';
fid = fopen( ffs, 'w' );
[~] = fprintf( fid, chr, 1.2, 3.4, 5.6, 7.8 );
[~] = fclose( fid );

I've changed the format specs in the file, model_v2.txt, to %3.1f because I assume that's what you intended.

Line 8 of model_out.txt now looks like

+tnom    = 27           toxe    = 1.2      toxp    = 3.4       toxm    = 5.6