Nested loops not working

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Mak 2017-5-30

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/342474-nested-loops-not-working

编辑： Mak 2017-5-31

Hi!

Been working at this problem for hours and just can't figure it out.

The FOR loop goes through numbers [9 11 12] and the WHILE loop is supposed to execute on each of the three iterations of the FOR loop. However, the FOR loop goes through all 3 iterations and then the while loop executes for the last iteration of the FOR loop. Why is the WHILE loop skipped on the first two iterations of the FOR loop?

Thanks a million to anyone who can help!

fid2=fopen('allMeasurements.txt','at');
for i = [9 11 12]
    s1=num2str(i);%Next lines creat filename
    if i<10;
        s0='0';
        s1=strcat(s0,s1);
    end
    s0='000';
    s=strcat(s0,s1,'.txt');
    sd='data';
    s=strcat(sd,s)
    fid=fopen(s, 'rt');
    while feof(fid)==0;%This loop goes through every even line of file
            tline = fgetl(fid);
            if mod(i,2)==1;
                continue
            end
            A = sscanf(tline,'%f', [1,4]);%The 4 colums are sotred in A
            B = A(3:end);%The last two colums are written to file
            fprintf(fid2,'%f %f\n',B);
    end
    fclose(fid);
end
fclose(fid2);

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Rik 2017-5-30

Try going through your code with breakpoints so you can follow the flow of your code step by step.

Also, you can use s=sprintf('data%05d.txt',i) to make your code look more elegant (and compatible with i>99).

Mak 2017-5-31

编辑：Mak 2017-5-31

SOLVED

I was insanely mixing up two the two loops:D

Thanks

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Answer 1

Jan 2017-5-30

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/342474-nested-loops-not-working#answer_268909

在 MATLAB Online 中打开

 However, the FOR loop goes through all 3 iterations and then the while loop executes for
 the last iteration of the FOR loop

I cannot confirm your opinion. Why do you assume that this happens?

folder = cd;  % Define it explicitely!
fid2 = fopen(fullfile(folder, 'allMeasurements.txt'), 'at');
if fid == -1
  error('Cannot open file for appending');
end
for i = [9 11 12]
  file = fullfile(folder, sprintf('data%05d.txt',i));
  fid  = fopen(file, 'rt');
  if fid == -1
    error('Cannot open file for reading: %s', file);
  end
  while feof(fid)==0   %This loop goes through every even line of file
      tline = fgetl(fid);
      if mod(i,2) == 0
        A = sscanf(tline, '%f', [1,4]);%The 4 colums are sotred in A
        fprintf(fid2, '%f %f\n', A(3:end));
      end
  end
  fclose(fid);
end
fclose(fid2);