Re: "inFile" object cannot read EOF

From:
 James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sun, 10 Jun 2007 11:50:10 -0000
Message-ID:
<1181476210.697644.85510@k79g2000hse.googlegroups.com>
On Jun 10, 2:23 am, Jerry Coffin <jcof...@taeus.com> wrote:

In article <1181292953.700106.187...@q66g2000hsg.googlegroups.com>,
james.ka...@gmail.com says...

[ ... ]

I'd write this loop something like:

    std::vector< donor > donors ;
    std::string line1 ;
    std::string line2 ;
    while ( getline( inFile, line1 ) && getline( inFile, line2 ) ) {
        double cash ;
        std::istringstream sCash( line2 ) ;
        sCash >> cash ;
        donors.push_back( donor( line1, cash ) ) ;
    }


Personally, I think I'd do it a bit differently:


I'd do it a lot differently in production code as well:-).
Starting with a lot more error handling.

struct donor {
        std::string name;
        double cash;

        // read a single donor's data:
        friend std::istream &operator>>(std::istream &i, donor &d) {
                std::getline(i, d.name);

                std::string line2;
                std::getline(line2);
                std::istringstream temp(line2);
                line2 >> d.cash;
                return i;
        }
};


Good point. Using a >> operator is definitely the way to go.

std::vector<donor> donors;

std::copy(std::istream_iterator<donor>(infile),
        std::istream_iterator<donor>(),
        std::back_inserter(donors));

This does not require (or allow) the count at the beginning of the file
though...


Neither did my version:-). In fact, as soon as you use
std::vector, you're freed from this constraint.

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