ifstream not reading EOF character

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不思量自难忘°
不思量自难忘° 2020-12-01 20:13

I am creating a program (In C++) that takes an ASCII file and reads a few values from each line until it reaches the end of the file. I am using ifstream to re

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  •  孤城傲影
    2020-12-01 21:19

    First thing is first, you shouldn't check like that. eof() doesn't return true until after a failed read. But you can do better (and easier)!

    check the stream state with the implicit conversion to void* which can be used in a bool context. Since most of the read operations on streams return a reference to the stream, you can write some very consice code like this:

    std::string line;
    while(std::getline(currentfile, line)) {
        // process line
    }
    

    Basically what it is doing is saying "while I could successfully extract a line from currentfile, do the following", which is what you really meant to say anyway ;-);

    Like I said, this applies to most stream operations, so you can do things like this:

    int x;
    std::string y;
    if(std::cin >> x >> y) {
        // successfully read an integer and a string from cin!
    }
    

    EDIT: The way I would rewrite your code is like this:

    string line;
    unsigned long pos = 0;
    int linenumber = 0;
    
    ifstream curfile(input.c_str());
    
    std::cout << "About to try to read the file" << std::endl;
    while (std::getline(curfile, line)) {
    
        std::cout << "Getting line " << linenumber << std::endl;
        linenumber++;
    
        // do the rest of the work with line
    }
    

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