Program to Implement Queue Data Structure using Linked Lists

C++/Program_25/Queues_Using_Linked_Lists.cpp

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+//Queues Using Linked List 
+#include<iostream>
+using namespace std;
+
+class node{
+    public:
+    int data;
+    node *link;
+}*front=NULL,*rear=NULL;
+
+void enqueue(int x){
+    node *t;
+    t = new node;
+    if(t==NULL)
+    cout<<"Queue is Full"<<endl;
+    else{
+        t->data = x;
+        t->link = NULL;
+    }
+    if(front==NULL){
+        front = rear = t;
+    }
+    else{
+        rear->link=t;
+        rear = t;
+    }
+}
+
+int dequeue(){
+    node *p;
+    int x = -1;
+    if(front==NULL)
+    cout<<"Queue is Empty!"<<endl;
+    else{
+        front = p->link;
+        x = p->data;
+        delete p;
+    }
+    return x;
+}
+
+void display(){
+    node *p=front;
+    while(p){
+        cout<<p->data<<" ";
+        p = p->link;
+    }
+    cout<<endl;
+}
+
+int main(){
+    int x;
+    char c;
+    while(1){
+    cout<<"Choose an Operation : \n1.Enqueue\n2.Dequeue\n3.Display\n4.Exit"<<endl;
+    cin>>c;
+    switch (c)
+    {
+    case '1':
+        cout<<"Enter the element : ";
+        cin>>x;
+        enqueue(x);
+        break;
+    case '2':
+        x=dequeue();
+        if(x!=-1)
+        cout<<"Deleted element is "<<x<<endl;
+        break;
+    case '3':
+        display();
+        break;
+    case '4':
+        return 0;
+        break;
+    default:
+        cout<<"Enter a valid option :("<<endl;
+        break;
+    }
+    }
+
+    return 0;
+}

C++/Program_25/README.md

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+Program to implement Queue DataStructure Using Linked Lists

C++/README.md

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 | Program-15 | Program to find modular exponentiation.
 | Program-19| To check whether a number is in palindrome or not
 | Program-24 | Program to convert Hexa-Decimal number to Decimal number 
+| Program-25 | Program to Implement Queue Data Structure Using Linked Lists