error: expected a type, got 'cmp'
main.cpp:31: error: type/value mismatch at argument 3 in template parameter list for 'template<class _Tp, class _Sequence, class _Compare> class std::priority_queue'
main.cpp:31: error: expected a type, got 'cmp'
template < class T, class Container = vector<T>,
class Compare = less<typename Container::value_type> > class priority_queue;
Compare: Comparison class: A class such that the expression comp(a,b), where comp is an object of this class and a and b are elements of the container, returns true if a is to be placed earlier than b in a strict weak ordering operation. This can either be a class implementing a function call operator or a pointer to a function.
不是可以用函数指针吗？为什么我的程序还会出错
#include<iostream> #include<functional> #include<queue> using namespace std; struct node {// friend bool operator< (node n1, node n2)// {// return n1.priority < n2.priority;// } int priority; int value; };//第一种是正确的//struct cmp{// bool operator() ( node a, node b ){// return a.priority < b.priority;// }//};//这种出错了bool cmp ( node a, node b ){ return a.priority < b.priority;} int main() { priority_queue<node, vector<node>, cmp> qn; ///error: expected a type, got 'cmp' node b[len]; b[0].priority = 6; b[0].value = 1; b[1].priority = 9; b[1].value = 5; b[2].priority = 2; b[2].value = 3; b[3].priority = 8; b[3].value = 2; b[4].priority = 1; b[4].value = 4; for(i = 0; i < len; i++) qn.push(b[i]); cout<<"优先级"<<'\t'<<"值"<<endl; for(i = 0; i < len; i++) { cout<<qn.top().priority<<'\t'<<qn.top().value<<endl; qn.pop(); } return 0; }