Reading text files

This is a discussion on Reading text files within the C++ Programming forums, part of the General Programming Boards category; Hi everyone! I'm just getting into C++ but I have a some experience in programming (if JavaScript counts...) anyways I ...

  1. #1
    carry on JaWiB's Avatar
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    Reading text files

    Hi everyone! I'm just getting into C++ but I have a some experience in programming (if JavaScript counts...)
    anyways I was wondering how you would check to see if there is text in a file (as opposed to none at all). For example in JavaScript I would do something like:

    Code:
    if (text_in_file!="") { ... }
    but it doesnt seem to work in C++...heres what i was doing in C++ (trimmed down to the problem):

    Code:
    char *str = new char[50];
    ifstream read_file("example.txt");
    read_file>>str;
    read_file.close(); 
    if (str!="") //<--heres where im stuck
     {
      //code goes here
     }
    else
     {
     //code goes here
     }
    "Think not but that I know these things; or think
    I know them not: not therefore am I short
    Of knowing what I ought."
    -John Milton, Paradise Regained (1671)

    "Work hard and it might happen."
    -XSquared

  2. #2
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    Heres a better way

    [code]
    #include <iostream>
    #include <fstream>

    int main()
    {
    char *Buffer;
    ifstream fin;

    Buffer= new char[80];
    fin.open("Example.txt");

    fin >> Buffer;
    fin.close();

    if( !Buffer )
    {
    cout << "Theres nothing in the text file!!"; << endl;
    }

    delete [] Buffer;
    cin.get();
    return 0;
    }

  3. #3
    carry on JaWiB's Avatar
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    Hm that doesn't seem to be working...are you sure the ( !Buffer ) is the right way to check if the file is empty?
    "Think not but that I know these things; or think
    I know them not: not therefore am I short
    Of knowing what I ought."
    -John Milton, Paradise Regained (1671)

    "Work hard and it might happen."
    -XSquared

  4. #4
    Registered User
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    or

    Code:
    #include <iostream>
    #include <fstream>
    
    int main()
    {
     char Buffer[80]
     fstream file("Example.txt", ios::in);
    
     file >> Buffer;
     
     if( !Buffer )    // Checks the contents of the buffer. If its empty then it proceeds the following code.
    {
     cout << "No text detected!!" << endl;
    }
    
     else
    {
     cout << Buffer << endl;
    }
    
     file.close();
     cin.get();
     return 0;
    }

  5. #5
    CS Author and Instructor
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    Cool

    Newbie helping a newbie!! There is an easier way!!
    Mr. C: Author and Instructor

  6. #6
    carry on JaWiB's Avatar
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    Heh still no luck. What's the cin.get(); for?
    "Think not but that I know these things; or think
    I know them not: not therefore am I short
    Of knowing what I ought."
    -John Milton, Paradise Regained (1671)

    "Work hard and it might happen."
    -XSquared

  7. #7
    Registered User
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    my bad, replace if( !Buffer ) with if( (strlen(Buffer))==0)

  8. #8
    carry on JaWiB's Avatar
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    ah ok thank you...im guessing the cin.get is to keep it from closing instead of using system("PAUSE")?
    "Think not but that I know these things; or think
    I know them not: not therefore am I short
    Of knowing what I ought."
    -John Milton, Paradise Regained (1671)

    "Work hard and it might happen."
    -XSquared

  9. #9
    Registered User
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    Yes, because system("PAUSE") is OS dependent.
    Last edited by alpha; 02-16-2003 at 11:01 PM.

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