Question

I wrote myself a compare function for sort(). It worked well when I put it this way.

bool comp(string a, string b)
{
    ...;
}

int main()
{
    sort(...,...,comp);
}

然而,当我把这一切放在一个班子里时,我要说:

class Test {

public:
    bool comp(string a,string b)
    {
        ...;
    }
    vector <string> CustomSort(vector <string> str) {
        sort(...,...,comp);
    }
};

There is a compile error "No matching function for call to sort ...... .

为什么会发生这种情况?

Answer 1

Any nonstatic member function of class X has an extra argument - a reference/pointer to (const) X which becomes this. Therefore a member function s signature isn t such that can be digested by sort. You need to use boost::bind or std::mem_fun or std::mem_fun_ref. When using C++11, you can use std::bind.

std::sort(..., ..., std::bind(&Test::comp, this, _1, _2));

想想一下,本案的最佳解决办法是使你的工作静态,因为它根本不需要<条码>。在这种情况下,你原来的法典将不加改动地发挥作用。

友情链接