lundi 2 mai 2016

istream::operator>> or istream::get

I was testing a block of code from the C++PL book and found the next piece of code (I didn't want to feel like I was copypasting it from the book to my IDE so I , at least, changed the variable names):

istream& operator>> (istream& is, MyContact& mc)
{
    char ch1, ch2;
    string ContactName{""};
    if (is>>ch1 && is>>ch2 && ch1=='{' && ch2=='"')
    {
        while(is>>ch1 && ch1 != '"')
            ContactName+=ch1;

        if (is>>ch1 && ch1==',')
        {
            int ContactAge=0;
            if (is>>ContactAge>>ch1 && ch1=='}')
            {
                mc={ContactName, ContactAge};        
                return is;
            }
        }
    }

    is.setstate(ios_base::failbit);
    return is;
}

According to this link istream::get "Extracts a single character from the stream"

And according to this link istream::operator>> "Extracts as many characters as possible from the stream"

Out of curiosity, I replaced

if (is>>ch1 && is>>ch2 && ch1=='{' && ch2=='"')

with

if (is.get(ch1) && is.get(ch2) && ch1=='{' && ch2=='"')

And it worked. No compilation errors and the program apparently did what it was supposed to do, now my question is:

Why is the operator >> used in the context where we extract a single char, when an is.get() would be equally functional?

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