Question

Implement a class of char Queue using the concept of array with the following member functions: push, pop (void), peek, empty, and full as explained in the lecture.

In C++

Answer 1

#include<iostream>

using namespace std;

class Queue {

public:

char* A;

int front = -1;

int rear = -1;

int aSize;

Queue() {}

Queue(int n) {A = new char[n];aSize = n;}

void Push(char x) { //O(1)

if (isFull()) { cout << "No space to store value" << endl; return; }

if (Empty()) {front++;}

//rear++;

rear = (rear+1) % aSize;

A[rear] = x;

}

bool Empty() { //O(1)

if (front == -1 && rear == -1) return true;

else return false;

}

bool isFull() { //O(1)

//if (rear >= aSize - 1) return true;

if (front == (rear + 1) % aSize) return true;

else return false;

}

void Print() { //O(n)

if (Empty()) { cout << "Nothing to print" << endl; return; }

if (front > rear) { //For circular queue

for(int i=front; i<aSize;i++)

cout << A[i] << " ";

for(int i=0;i<=rear; i++)

cout << A[i] << " ";

}

else { //For normal queue

for (int i = front; i <= rear; i++) {

cout << A[i] << " ";

}

}

cout << endl;

}

void Pop() { //O(1)

if (front == rear && front != -1){ //Last element in the queue

front = -1;

rear = -1;

}

else {

front = (front+1)%aSize;

}

}

char DequeBack(){

char value = A[front];

if (front == rear && front != -1){

value = A[front];

front = -1;

rear = -1;

}

else {

front = (front+1)%aSize;

}

return value;

}

char Peek(){

if (Empty()) { cout << "Queue is Empty" << endl; return '%'; }

char value = A[front];

return value;

}

};

int main() {

Queue* queue = new Queue(6);

queue->Push('A'); queue->Print();//A

queue->Push('B'); queue->Print();//A B

queue->Push('C'); queue->Print();//A B C

queue->Push('D'); queue->Print();//A B C D

cout << "Peek: "<<queue->Peek() << endl;

queue->Print();

queue->Pop();

cout << "After Popping an element, the queue is: ";

queue->Print();

}

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SEE OUTPUT

Files > clang++-7 -pthread -std=c++17 -o main main.cpp > ./main main.cpp A AB ABC ABCD Peek: A ABCD After Popping an element, the queue is: BCD main.cpp E 1 2 #include<iostream> 3 using namespace std; 4 5 class Queue { 6 public: 7 char* A; 8 int front = -1; 9 int rear = -1; 10 int aSize; 11 Queue () {} 12 Queue (int n) {A = new char[n];aSize = n; } 13 void Push (char x) { //0(1) 14 if (isFull()) { cout << "No space to store value" << endl; return; } 15 if (Empty() [front++; } 16 //rear++; 17 rear = (rear+1) % aSize; 18 A[rear] = x; 19 20 bool Empty() { //0(1) 21 if (front == -1 && rear == -1) return true; 22 else return false; 23 } 24 bool isFull() { //0(1) 25 //if (rear >= aSize - 1) return true; 26 if (front == (rear + 1) % aSize) return true; 27 else return false; 28 29 void Print() { //0(n) } }

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