Thread: reading data contents from files in c++

  1. #1
    Registered User
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    reading data contents from files in c++

    Hello there. Well im stuck with a problem of how to extract data from a given data file. i have to read line by line. for example:

    this line contains numbers(int):
    2 3 4 5 6

    i have to read each of these and assign each to a variable that i"ll be able to calculate the sum.


    another line:conataining floating pt numbers. same thing to do here.

    and lastly of how to concatenate some characters to form a string, the characters will be read from the data file.

    Any suggestion plz...

  2. #2
    Confused Magos's Avatar
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    In its most simple form:
    Code:
    int Var1;
    int Var2;
    float Var3;
    float var4;
    
    std::ifstream File("SomeFile.txt");
    
    File >> Var1 >> Var2 >> Var3 >> Var4;
    MagosX.com

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    Teach a man to fish and you feed him for a lifetime.

  3. #3
    Code Injector Gaming's Avatar
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    That could work..

  4. #4
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    yea.. this is fine... but i have those integers, floating points and characters on separate lines in a single file.. how do i proceed then???

  5. #5
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    ...on separate lines in a single file...
    Doesn't matter. By default ifstream delimits on spaces, newlines, and tabs - meaning a new line is like a space to ifstream. Therefore, what Magos suggested would work.

    and lastly of how to concatenate some characters to form a string, the characters will be read from the data file.
    What kind of string? C-string or std::string? C-strings are just char arrays (but remember to tack on a '\0' to the end). As for std::string, it has a push_back() function.
    http://www.cppreference.com/cppstring/push_back.html

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