CPP Queue

Queue is a data structure in CPP that works on FIFO (First In First Out) technique, which means that the first inserted element will be deleted first in a queue.

Syntax:

template<class T, class Container = deque<T> > class queue;

Member Types of CPP Queue:

MEMBER TYPE	USES
container_type	To specify underlying container type.
const_reference	To specify the reference type of constant container.
size_type	To specify the size range of the elements.
value_type	To specify the element type.
reference	To specify the reference type of container.

CPP Queue Functions:

FUNCTION	USES
back	To access the rear element of the queue.
(constructor)	To construct a queue container.
empty	To test for the emptiness of a queue and to get a true value if the queue is empty.
emplace	To insert a new element in the queue above the current rear end element.
front	To access the front element of the queue.
push	To insert a new element at the rear end of the queue.
pop	To delete the element in the queue from the front end.
swap	To interchange the contents of two containers in reference.
size	To return the size of the queue container, which is a measure of the number of elements stored in the queue.

Example:

#include <iostream.h>  
#include <queue.h>  
using namespace std;  
void display(queue <int> ds)  
{  
queue <int> dis = ds;  
while (!dis.empty())  
{  
	cout << dis.front() << " ";  
	dis.pop();  
}  
}  
 
int main()  
{  
queue <int> getqueue;  
getqueue.push(80);  
getqueue.push(60);  
getqueue.push(50);  
getqueue.push(30);  
 
cout << "The Queue element from first to last are  : ";  
display(getqueue);  
 
cout << "\nThe value of getqueue.size() : " << getqueue.size();  
cout << "\nThe value of getqueue.front() : " << getqueue.front();  
cout << "\nThe value of getqueue.back() : " << getqueue.back();  
 
cout << "\nThe value of getqueue.pop() : ";  
getqueue.pop();  
display(getqueue);  
 
return 0;  
}

Output

The Queue element from first to last are : 80 60 50 30                                          
The value of getqueue.size() : 4                      
The value of getqueue.front() : 80                    
The value of getqueue.back() : 30   
The value of getqueue.pop() : 60 50 30

CPP examples programs