无法正确执行 std::sort

Question

After doing some research I have resigned to ask what is going wrong with std::sort .

Following Oliver Charlesworth advice from here I created a comparative, included the algorithm header and called std::sort in my function. I am still getting errors. Probably an oversight but still.

Errors:

Error C2780 void std::sort(_RanIt,_RanIt)': expects 2 arguments - 3 provided

Error C2672 'std::sort': no matching overloaded function found

Error C3867 'ImageEvaluator::comparator': non-standard syntax; use '&' to create a pointer to member

Struct:

struct numLocWidth
{
    int width;
    int number;
    int location;
};

Comparative:

bool comparator(const numLocWidth &a, const numLocWidth &b) 
{ 
    return a.location < b.location; 
}

Function:

if (tempMax > minAcceptableValue)
{
    tempLocAndVal.location = max_Pot_Loc.x;
    tempLocAndVal.number = i - 1;
    tempLocAndVal.width = templates[7][i].size().width;
    foundNumbers.push_back(tempLocAndVal);
    std::sort(foundNumbers.begin(), foundNumbers.end(), comparator);                
}

Not sure what is going on here and have been scratching my head for a bit. I could write my own sort function but I'm pretty sure this way will be more efficient.

Answer 1

As VTT and Peter rightly pointed out, my comparative needed to be marked as static because it was a member of a class.

More information on this can be found here under requirements and BinaryPredicates.

Thanks for the help

Solution. From:

bool comparator(const numLocWidth &a, const numLocWidth &b) 
{ 
    return a.location < b.location; 
}

To:

static bool comparator(const numLocWidth &a, const numLocWidth &b) 
{ 
    return a.location < b.location; 
}

Thanks again for the help