reading a float from file

This is a discussion on reading a float from file within the C++ Programming forums, part of the General Programming Boards category; I'm having a problem reading float data type from file. The file is structured so that sets of float values ...

  1. #1
    Registered User
    Join Date
    Feb 2003
    Posts
    5

    reading a float from file

    I'm having a problem reading float data type from file. The file is structured so that sets of float values would be separated by -99. (ie. 5.43, 6.78, 4.35, -99, 4.32, etc...). The -99 would flag the beginning of the next set. When I initially wrote the program, integers were saved to the file, and reading them back in were no problem. But then I modified the code to read and write floats, and it doesn't read them anymore. I've tried a couple of different ways:

    Code:
       data >> temp; //data is file, temp is var
       data.getline (temp, sizeof(temp))
    but both methods skip all the floats and only read in the -99. temp is declared as float. Why is this happening? How can I read in the float values? I've checked around, but can't find a specific answer to this. Any help would be greatly appreciated.

  2. #2
    samurai warrior nextus's Avatar
    Join Date
    Nov 2001
    Posts
    196
    maybe your temp variable is an integer..it worked fine for me..my text file looked like this

    Code:
    99 5.43 6.78 4.35
    and here is the code
    Code:
    #include <iostream.h>
    #include <fstream.h>
    
    
    int main()
    {
    	ifstream a_file("date.txt", ios::nocreate);
    	float var = 0.0f;
    
    	while(a_file.eof() == false)
    	{
    		a_file >> var; //should skip white spaces and store number;
    		cout << var << endl;
    	}
    
    	return 0;
    }
    hope that helps
    nextus, the samurai warrior

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