Avoiding Error Flags when Reading Files

This is how I usually read files with std::ifstream:

while (InFile.peek() != EOF)
{
    char Character = InFile.get();
    // Do stuff with Character...
}

开发者_JAVA百科

This avoids the need of an if statement inside the loop. However, it seems that even peek() causes eofbit to be set, which makes calling clear() necessary if I plan on using that same stream later.

Is there a cleaner way to do this?

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Typically, you would just use

char x;
while(file >> x) {
    // do something with x
}
// now clear file if you want

If you forget to clear(), then use an RAII scope-based class.

Edit: Given a little more information, I'd just say

class FileReader {
    std::stringstream str;
public:
    FileReader(std::string filename) {
        std::ifstream file(filename);
        file >> str.rdbuf();
    }
    std::stringstream Contents() {
        return str;
    }
};

Now you can just get a copy and not have to clear() the stream every time. Or you could have a self-clearing reference.

template<typename T> class SelfClearingReference {
    T* t;
public:
    SelfClearingReference(T& tref)
        : t(&tref) {}
    ~SelfClearingReference() {
        tref->clear();
    }
    template<typename Operand> T& operator>>(Operand& op) {
        return *t >> op;
    }
};

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I'm not sure I understand. Infile.peek() only sets eofbit when it returns EOF. And if it returns EOF, and later read is bound to fail; the fact that it sets eofbit is an optimization, more than anything else.