Description

A queue is an abstract data type that serves as a collection of elements, where nodes are removed only from the head of the queue and are inserted only at the tail of the queue. Two principal operations can be used to manipulate a queue: enqueue, which inserts an element at the tail, and dequeue, which removes the element at the head of the collection.

Let’s see how the queue data structure can be realized in C++.We have an approach to implement queue: linked list. Thus, we define a class as follows:

 class List_queue {

    public:

        List_queue();

        ~List_queue();

        void enqueue(const int &);

        void dequeue();

        void print();

    private:

        ListNode *head;

        ListNode *tail;

};

where List_queue implements the queue data structure.

REQUIREMENTS:

Implement the constructor, destructor, enqueue(), dequeue() and print() member functions of the List_queue class.

Note:

1.This problem involves three files.

• function.h: Class definitions.
• function.cpp: Member-function definitions.
• main.cpp: A driver program to test your class implementation.

You will be provided with main.cpp and function.h, and asked to implement function.cpp.

function.h

#ifndef FUNCTION_H #define FUNCTION_H #include <iostream> class ListNode { friend class List_queue; //make List_queue a friend public: ListNode( const int &info ) //constructor : data( info ), nextPtr( NULL ), prevPtr( NULL ) { } //end ListNode constructor private: int data; //data ListNode *nextPtr; // next node in list ListNode *prevPtr; }; //end class ListNode class List_queue { public: List_queue(); ~List_queue(); void enqueue(const int &); void dequeue(); void print(); private: ListNode *head; ListNode *tail; }; #endif

main.cpp

#include<iostream> #include<string.h> #include "function.h" using namespace std; int main(){ List_queue L_queue; char command[10]; int n; while(cin>>command){ if(strcmp(command,"dequeue")==0){ L_queue.dequeue(); }else if(strcmp(command,"enqueue")==0){ cin >> n; L_queue.enqueue(n); }else if(strcmp(command, "print") == 0){ L_queue.print(); cout << endl; } } return 0; }

2.For OJ submission:

       Step 1. Submit only your function.cpp into the submission block.

       Step 2. Check the results and debug your program if necessary.

Input

There are three kinds of commands:

• “enqueue integerA” represents inserting an element with int value A at the tail of the queue.
• “dequeue” represents removing the element at the head of the queue.
• “print” represents showing the current content of the queue.

Each command is followed by a new line character.

Input terminated by EOF.

Output

The output should consist of the current state of the queue.

When the queue is empty, you don’t need to print anything except a new line character.

Sample Input  Download

Sample Output  Download

Partial Judge Code

10997.cpp

Partial Judge Header

10997.h

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Description

Warning: You are not allowed to use:

1. any static variables

2. any variables which is not inside a function

3. malloc and free

The storage of the vector is handled automatically, being expanded and contracted as needed. Vectors usually occupy more space than static arrays, because more memory is allocated to handle future growth. This way a vector does not need to reallocate each time an element is inserted, but only when the additional memory is exhausted.

REQUIREMENTS:

Implement the push_back(), pop_back(), reserve() and destructor member functions of Vector classes.

Note:

If the value of size is equal to the value of capacity, and you need to change the value of capacity (reallocate memory) when you push_back a new element. The rule of increasing capacity is: new capacity = max(old capacity + 1, old capacity * 3).

The constructor of vector will not create an array (which means size and capacity is 0).

Input

here are five kinds of commands:

• pop_back: removes the last element
• push_back: adds an element to the end
• capacity: returns the number of elements that can be held in currently allocated storage
• size: returns the number of elements
• reserve: reserves storage (Increase the capacity of the container to a value that's equal to new capacity. If new capacity is greater than the current capacity, new storage is allocated, otherwise the method does nothing.)

Each commands is followed by a new line character ('\n').

Output

The output should consist of the current state of the vector.

Sample Input  Download

Sample Output  Download

Partial Judge Code

11420.cpp

Partial Judge Header

11420.h

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Discuss