Only the last user input is being stored, the rest are being replaced by zeros in my array.

Question

James 2016-10-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/308851-only-the-last-user-input-is-being-stored-the-rest-are-being-replaced-by-zeros-in-my-array

评论： James 2016-10-24

Hi all, This code is meant to take user input, and store it onto a text file, however when n > 1 in my code, it will only store the last user input into the array, and replace all the previous values (of y,x,z) inputed with 0. How can this be resolved? Here is my code:

fid1 = fopen('set_p.txt','w');
prompt2 = 'How many data sets do you want to take?\n';
n = input(prompt2);
p = n-1;
clearvars x y z;
for j = 1:n
  prompt3 = 'How long do you want the test to run (s)?\n';
  y(n) = input(prompt3);
  prompt4 = 'What sampling interval do you want to have (s)?\n';
  x(n) = input(prompt4);
  if p == 0
     z = 0;       
  elseif j <= p
      prompt5 = 'How long do you want between each data set (s)?\n';
      z(p) = input(prompt5);    
  end
end
fprintf(fid1, '%6.3f,',n,y,x,z);
fclose(fid1);

Thanks for all the help in advance!

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Answer 1

Jan 2016-10-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/308851-only-the-last-user-input-is-being-stored-the-rest-are-being-replaced-by-zeros-in-my-array#answer_240414

编辑：Jan 2016-10-24

在 MATLAB Online 中打开

fid1 = fopen('set_p.txt', 'w');
% Never never never open a file without test for success:
if fid == -1, error('Cannot open file.'), end
prompt2 = 'How many data sets do you want to take?\n';
prompt3 = 'How long do you want the test to run (s)?\n';
prompt4 = 'What sampling interval do you want to have (s)?\n';
prompt5 = 'How long do you want between each data set (s)?\n';
n = input(prompt2);
p = n-1;
x = zeros(1, n);  % Pre-allocate in general
y = zeros(1, n);
z = zeros(1, n);
for j = 1:n
  y(j) = input(prompt3);   % Not y(n), which writes the last element only
  x(j) = input(prompt4);
  if p == 0   % 
     z(j) = 0;       
  elseif j <= p
     z(j) = input(prompt5);    % Not z(p), I guess
  end
end
fprintf(fid1, '%6.3f,', n, y, x, z);
fclose(fid1);