Priority_queue in C++

This C++ Program demonstrates implementation of Priority_queue in STL.

Here is source code of the C++ Program to demonstrate Priority_queue in STL. The C++ program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C++ Program to Implement Priority_queue in Stl

```
 */
```
```
#include <iostream>
```
```
#include <queue>
```
```
#include <string>
```
```
#include <cstdlib>
```
```
using namespace std;
```
```
int main()
```
```
{
```
```
    priority_queue<int> pq;
```
```
    int choice, item;
```
```
    while (1)
```
```
    {
```

        cout<<"\n---------------------"<<endl;

        cout<<"Priority Queue Implementation in Stl"<<endl;

        cout<<"\n---------------------"<<endl;

        cout<<"1.Insert Element into the Priority Queue"<<endl;

        cout<<"2.Delete Element from the Priority Queue"<<endl;

	cout<<"3.Size of the Priority Queue"<<endl;

        cout<<"4.Top Element of the Priority Queue"<<endl;

```
        cout<<"5.Exit"<<endl;
```
```
        cout<<"Enter your Choice: ";
```
```
        cin>>choice;
```
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        switch(choice)
```
```
        {
```
```
        case 1:
```

            cout<<"Enter value to be inserted: ";

```
            cin>>item;
```
```
            pq.push(item);
```
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            break;
```
```
        case 2:
```
```
            item = pq.top();
```
```
            if (!pq.empty())
```
```
            {
```
```
                pq.pop();
```

                cout<<"Element "<<item<<" Deleted"<<endl;

```
            }
```
```
            else
```
```
            {
```

                cout<<"Priority Queue is Empty"<<endl;

```
            }
```
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            break;
```
```
        case 3:
```

            cout<<"Size of the Queue: ";

```
	    cout<<pq.size()<<endl;
```
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            break;
```
```
        case 4:
```

            cout<<"Top Element of the Queue: ";

```
            cout<<pq.top()<<endl;
```
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            break;
```
```
        case 5:
```
```
            exit(1);
```
```
	    break;
```
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        default:
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```
            cout<<"Wrong Choice"<<endl;
```
```
        }
```
```
    }
```
```
    return 0;
```
```
}
```

$ g++ priority_queue.cpp
$ a.out
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 5
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 3
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 7
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 4
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 2
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 1
Enter value to be inserted: 8
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 3
Size of the Queue: 6
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 4
Top Element of the Queue: 8
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 2
Element 8 Deleted
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 3
Size of the Queue: 5
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 4
Top Element of the Queue: 7
 
---------------------
Priority Queue Implementation in Stl
 
---------------------
1.Insert Element into the Priority Queue
2.Delete Element from the Priority Queue
3.Size of the Priority Queue
4.Top Element of the Priority Queue
5.Exit
Enter your Choice: 5
 
 
------------------
(program exited with code: 1)
Press return to continue