Declaring a Priority Queue with a Custom Comparator in C

In C , when attempting to declare a priority queue that utilizes a custom comparator, it is essential to define the comparator correctly. The error "Compare" is not a type name arises when the comparator is not declared as a class or a standalone function.

To resolve this, you can define a class for the comparator and overload the operator() for it, as demonstrated in the following example:

class Compare
{
public:
    bool operator() (Node a, Node b)
    {
        // Comparator logic
    }
};

Alternatively, you can utilize a std::function to define the comparator, as shown below:

bool Compare(Node a, Node b)
{
    // Comparator logic
}

std::priority_queue, std::function> pq(Compare);

By following these approaches, you can effectively declare a priority queue with a custom comparator in C .