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  1. #include <iostream>
  2. #include <stack>
  3. #include <queue>
  4. #include <vector>
  5. #include <algorithm>
  6. #include <iterator>
  7. using namespace std;
  8.  
  9. template<class T> void print_queue(T& q) {
  10.     while(!q.empty()) {
  11.         std::cout << q.top() << " ";
  12.         q.pop();
  13.     }
  14.     std::cout << '\n';
  15. }
  16.  
  17. template<class T> 
  18. class priority_stack {
  19. 	vector<T> stack;  
  20. public:  
  21.     bool empty() const { return stack.size()==0; } 
  22.     void push(const T& x) { 
  23.     	stack.push_back(x); 
  24.     	for (int i=stack.size()-1; i!=0; i--)
  25.     	    if ( (stack[i]<stack[i-1]))            // assuming priority is reflected in order of elements
  26.     	        swap (stack[i-1],stack[i]);
  27.     }  
  28.     void pop() {
  29.         if (! empty() )
  30.             stack.resize(stack.size()-1);
  31.     }
  32.     T top() { 
  33.     	if (empty()) 
  34.     	    throw; 
  35.     	return stack[stack.size()-1]; 
  36.     }  
  37. };
  38.  
  39.  
  40. struct data {
  41.     int priority; 
  42.     string message;  
  43.     bool operator< (const data&a) const {
  44.     	return priority<a.priority;  
  45.     } 
  46. };
  47.  
  48. ostream& operator<< (ostream& os, const data &x) {
  49. 	return os<<"("<<x.priority<<","<<x.message<<")";
  50. }
  51.  
  52.  
  53. int main() {
  54. 	vector<data> d{ { 10, "one"}, {10, "two"}, {11,"high"}, {12,"very high"}, {10,"three"} };
  55.     cout << "Data to be pushed:";
  56.     copy (d.cbegin(), d.cend(), ostream_iterator<data>(cout," "));
  57.     cout<<endl;
  58.  
  59.     cout << "Priority queue (FIFO): ";	
  60.     std::priority_queue<data, std::vector<data>> pq;
  61.     for (auto x: d) 
  62.         pq.push(x);
  63.     print_queue(pq);
  64.  
  65.     cout << "Priority stack (LIFO): ";	
  66.     priority_stack<data> ps; 
  67.     for (auto x: d) 
  68.         ps.push(x);
  69.     print_queue(ps);
  70.  
  71.  	return 0;
  72. }
Success #stdin #stdout 0s 15248KB
comments (?)
stdin 
Standard input is empty
stdout 
Data to be pushed:(10,one) (10,two) (11,high) (12,very high) (10,three) 
Priority queue (FIFO): (12,very high) (11,high) (10,one) (10,two) (10,three) 
Priority stack (LIFO): (12,very high) (11,high) (10,three) (10,two) (10,one)
https://ideone.com/fekbyc
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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