Reading numbers from txt file

For example, this is a content of some txt file:
0.2 0.3 0.1 1.6
I'd like to load these numbers in some array and use them in a program. How do I do that?

Use a loop. Unless you know there will always be a fixed number of values in the file to read into the array, you'd be better off reading into a vector instead (or some other STL container) since it will grow to accommodate any number of values.

Basics of File I/O here

Quote:

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Originally Posted by hk_mp5kpdw

Use a loop. Unless you know there will always be a fixed number of values in the file to read into the array, you'd be better off reading into a vector instead (or some other STL container) since it will grow to accommodate any number of values.

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Of course, vector is better, I said array for simplicity. I can't use a loop, becoase I don't know the basis of reading from files. I'm not asking for algoritam (although I would not mind :) ), just commands that can help read list of numbers from a txt file.
Richie T gave the link, but I really can't understand how to solve my problem just by knowing how to open a file. I'd like to know how to read from some position in file, and then when program reads the data, that it can convert it to double, becoase I need it to read numbers not string. If anyone can help, I would appreciate it.

It's really simple, basically you want to do something similar to this:

Code:

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#include <fstream>
#include <vector>
using namespace std;

...

ifstream in("NameOfFile.txt");  // ifstream objects are for reading
vector<double> dbl_vect;        // vector container to hold values read from file
double temp;                    // Temporary variable

while( in >> temp )            // While there is stuff to read from file...
    dbl_vect.push_back(temp);  // ... push double read from file onto vector

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edit: If you don't want a loop in your code, you can use the copy function in the <algorithm> header to replace the while loop and push_back lines in the example above as follows:

Code:

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#include <algorithm>
#include <iterator>

...

copy(istream_iterator<double>(in),istream_iterator<double>(),back_inserter(dbl_vect));

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You also wouldn't need the temp variable.

Thank you very much, this works! :)