我的条件最小搜索失败。 我该如何解决这个问题？ C++

Question

I have an input.txt that looks like this:
(in this order: angler, contest, fish, weight)

JACK random3030 fish 10 fish 12.6
JOHN random3030 fish 5.3 fish 4.5
THOMAS xyz0501 carp 2 carp 5 fish 3 carp 6
SMITH xyz0501 carp 40 fish 3

What I would like to achieve is to print the minimum weight of a carp. My code fails when there are more than 1 carp in the same row. So output should be:

THOMAS has caught a carp with the minimum weight of 2 on contest xyz0501

My output looks like this:

THOMAS has caught a carp with the minimum weight of 6 on contest xyz0501

So if there are more than 1 carp in a row, my output always prints the latest, not the mininum. Important to note that it is possible to not have a single carp in the input.txt. Also, if I put this in the input.txt:

SMITH xyz0501 carp 1 carp 40 fish 3

instead of this:

SMITH xyz0501 carp 40 fish 3

My output is still the same while it should be SMITH since he has caught the minimum weight.
My code:

int main()
{
    string filename;
    cout<<"Enter the name of the input file, please: ";
    cin>>filename;

//conditional min search
try
{
    Contest e;
    double minWeight=999;
    ContestEnor t(filename);
    bool l = false;
    for(t.first(); !t.end(); t.next())
    {

        if(!l && t.current().weight < minWeight)
        {
            l=true;
            e=t.current();
            minWeight=t.current().weight;
        }
        else if(l && t.current().weight < minWeight)
        {
            if(e.weight < minWeight)
                e=t.current();
            minWeight=t.current().weight;
        }
    }
    cout<<e.angler<<" has cought a carp with the lowest weight of "<< minWeight <<" on contest "<<e.contest<<endl;
}
catch(ContestEnor::FileError err)
{
    cerr<<"Can't find the input file:"<<filename<<endl;
}  
}

weight.hpp

struct Contest
{
    string angler;
    string contest;
    int counter;
    double weight;
};


   //This is the enumerator   
class ContestEnor  
{  
private:  
    ifstream _f;  
    Contest _cur;  
    bool _end;   

public:
    enum FileError {MissingInputFile};
    ContestEnor(const string &str) throw (FileError);
    void first()
    {
        next();
    }
    void next();
    Contest current() const
    {
        return _cur;
    }
    bool end() const
    {
        return _end;
    }
};


ContestEnor::ContestEnor(const string &str) throw (FileError)
{
    _f.open(str);
    if(_f.fail())
        throw MissingInputFile;
}

void ContestEnor::next()
{
    string line;
    getline(_f, line);
    if( !(_end = _f.fail()) )
    {
        istringstream is(line);
        is >> _cur.angler >> _cur.contest;
        _cur.counter = 0;
        string fish;
        int _size;
        for( is >> fish >> _size ; !is.fail(); is >> fish >> _size )
        {
            if(fish == "carp")
                _cur.weight=_size;
        }
    }
}

I think my main for cycle has something to do with my problem (thanks to debug) but there might be more that I don't know of. I recently started practicing more with classes and stuff, so please keep the solution as simple as you can. Thank you.

Answer 1

if there are more than 1 carp in a row, my output always prints the latest,

I believr this happens because the code reading the file stores ONLY the last carp in a line

    for( is >> fish >> _size ; !is.fail(); is >> fish >> _size )
    {
        if(fish == "carp")
            _cur.weight=_size;
    }

This loop will run twice if there are two carp in a line. The second time it will over-write the weight of the first with the weight of the second. That is why you can only see the weight of the last carp in each line.

Every carp should have its own record ( 1:1 ). If a fisher catches two carp. then the fisher should have two records, one for each carp ( 1:n )

Each time the file reader encounters another carp, it should create and store a new record.