MATLAB: Counter Values Are Not Changing, MATLAB

fprintf

I am new to Matlab and I have an issue where two counters in my code do not change value.
 fid = fopen('results.txt', 'wt');
 counter1 = 0;
 counter2 = 3;
 for i=1:size(res_t,1)
    counter1 = counter1 + 1;
    if(counter2 == 3)
      fprintf(fid, '%f ', res_t.time(:,:)); % first column i need the time
      counter2 = 0;
    end   
     fprintf(fid, '%f ', res_t.data(:,:)');
     if(counter1 == 3)
            fprintf(fid, '\n'); %after it writes all 3 X,Y,Z i want to change line
            counter1 = 0;
     end
     counter2 = counter2 + 1;
 end
 fclose (fid);
}
When compiled, the values of counter1 & counter2 do not change, which means they never meet the If statement conditions. My output file is a file which contains: column1: time values, columns2 to 4: X, Y, Z coordinates respectively.
For example:
Time1 X1 Y1 Z1
Time2 X2 Y2 Z2
Thanks!

Best Answer

Probably because
size(res_t,1)
is either empty or 0 so the loop never executes.
You say "when compiled"; is that a euphemism or are you really building a compiled .exe? I've never had the toolbox so don't know what/how it deals with undefined variables when it finds one--at the command line if res_t didn't exist you'd error and know what the problem is.
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