STL Series 5: Queue container and stl series queue container

STL Series 5: Queue container and stl series queue container
Queue Introduction

• Queue is a queue container and a "first-in-first-out" container.
• Queue is a simple deque container and becomes another container.
• # Include <queue>

1. Default Construction of the queue object

The queue is implemented using the template class. The default construction form of the queue object is queue <T> queT; for example, queue <int> queInt; // a queue container that stores the int. Queue <float> queFloat; // a queue container that stores float .... // You can also set the pointer type or custom type in the angle brackets.

2. The push () and pop () Methods of queue

• Queue. push (elem); // add elements to the end of the team
• Queue. pop (); // remove the first element from the queue Header

# Include <iostream> using namespace std; # include <queue> void objPlay2 () {queue <int> queInt; queInt. push (1); queInt. push (3); queInt. push (5); queInt. push (7); queInt. push (9); queInt. pop (); queInt. pop (); // The elements stored in the queInt are 5, 7, 9} int main () {objPlay2 (); return 0 ;}

 

3. Copy construction and assignment of the queue object

• Queue (const queue & que); // copy the constructor
• Queue & operator = (const queue & que); // overload the equal sign operator

Void objPlay3 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); queue <int> queIntB (queIntA); // copy and construct the queue <int> queIntC; queIntC = queIntA; // assign value}

4. Data Access to queue

• Queue. back (); // returns the last element.
• Queue. front (); // returns the first element.

Void objPlay4 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); int iFront = queIntA. front (); // get the queue Header element, 1 int iBack = queIntA. back (); // get the end element of the queue, 9 queIntA. front () = 11; // 11 queIntA. back () = 19; // 19}

5. queue size

• Queue. empty (); // determines whether the queue is empty.
• Queue. size (); // the size of the returned queue

  Void objPlay5 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); if (! QueIntA. empty () {int iSize = queIntA. size (); // There are five elements in the queue }}

   

 Sort all the above Code:

# Include <iostream> using namespace std; # include <queue> void objPlay2 () {queue <int> queInt; queInt. push (1); queInt. push (3); queInt. push (5); queInt. push (7); queInt. push (9); queInt. pop (); queInt. pop (); // The elements stored in the queInt are 5, 7, 9} void objPlay3 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); queue <int> queIntB (queIntA); // copy and construct the queue <int> queIntC; qu EIntC = queIntA; // value assignment} void objPlay4 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); int iFront = queIntA. front (); // get the queue Header element, 1 int iBack = queIntA. back (); // get the end element of the queue, 9 queIntA. front () = 11; // 11 queIntA. back () = 19; // 19} void objPlay5 () {queue <int> queIntA; queIntA. push (1); queIntA. push (3); queIntA. push (5); queIntA. push (7); queIntA. push (9); if (! QueIntA. empty () {int iSize = queIntA. size (); // Five Elements in the queue} int main () {objPlay2 (); objPlay3 (); objPlay4 (); objPlay5 (); return 0 ;}