Problem with reading of file

This is a discussion on Problem with reading of file within the C++ Programming forums, part of the General Programming Boards category; Hi all, I am generating a value by calling some fn which returns uint32_t and storing these values in file. ...

  1. #1
    Registered User
    Join Date
    May 2010
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    9

    Problem with reading of file

    Hi all,
    I am generating a value by calling some fn which returns uint32_t and storing these values in file. Part of Code as shown below
    Code:
    //to write content in file
    uint32_t c;
    ofstream outfile;
    	outfile.open("output",ios::app|ios::out|ios::binary);
    // putting value in file using loop
    outfile<<c;
    //to read content of file
    ifstream myfile ("output");
    	myfile.is_open();
    	myfile>>num;  // for first record display
    printf("value fetched from file: %.8x\n", num); 
    
    int record = 2* sizeof(uint32_t);     //offset to reach third record
    	myfile.seekg( record, ios::beg);
    	myfile>>num1;
    	printf("value fetched from file: %.8x\n", num1); 
    	myfile.close();
    the above code gives some garble value. I tried the next code which gives me just the first value and with offset again gives garble values.
    Code:
    ofstream outfile;
    	outfile.open("output");
    outfile<<c<<endl;
    File "output" contains the value but i am not able to read the value, may be problem with the offset.
    pl help
    rgds

  2. #2
    and the Hat of Guessing tabstop's Avatar
    Join Date
    Nov 2007
    Posts
    14,185
    It is probably a good idea to open your input file with binary if you wrote it with binary.

  3. #3
    Registered User
    Join Date
    May 2010
    Posts
    9

    Unhappy

    Hi
    I have refined my code as under but no success so far
    Code:
     
    ifstream myfile ("output",ios::in|ios::binary);

  4. #4
    Registered User
    Join Date
    May 2010
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    2,693
    You should probably be using the read() and write() member functions when dealing with binary files, as there may not be any separation of the values ,

    Jim
    Last edited by jimblumberg; 05-28-2010 at 06:06 AM.

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