priority_queue<> comparison for pointers?

Question

So I\'m using the STL priority_queue<> with pointers... I don\'t want to use value types because it will be incredibly wasteful to create a bunch of new objects just for

Answer 1

You can explicitly specify which comparator your queue should use.

#include 
#include 
#include 
#include 
#include 

class Int {
public:
    Int(int val) : m_val(val) {}
    int getVal() { return m_val; }
    bool operator<(const Int &other) const { return m_val < other.m_val; }
private:
    int m_val;
};

template >
struct pless : public std::binary_function {
    bool operator()(const Type *x, const Type *y) const
        { return Compare()(*x, *y); }
};

int main(int argc, char *argv[]) {
    std::priority_queue, pless > myQ;

    for (int i = 1; i < argc; i++) {
        std::stringstream ss(argv[i]);
        int x;
        ss >> x;
        myQ.push(new Int(x));
    }

    for (; !myQ.empty(); delete myQ.top(), myQ.pop())
        std::cout << myQ.top()->getVal() << std::endl;

    return 0;
}