From d7eeba8a481d4cb6f019f588a21bc875996e1a35 Mon Sep 17 00:00:00 2001
From: Wander_lust <hvmanoj2@gmail.com>
Date: Thu, 22 Jan 2026 17:38:03 +0530
Subject: [PATCH] Refactor queue implementation in QueueInLL.c

---
 QueueInLL.c | 180 ++++++++++++++++++++++------------------------------
 1 file changed, 75 insertions(+), 105 deletions(-)

diff --git a/QueueInLL.c b/QueueInLL.c
index 7a81672..ec142cc 100644
--- a/QueueInLL.c
+++ b/QueueInLL.c
@@ -1,128 +1,98 @@
-#include <stdio.h>
-#include <stdlib.h>
+#include<stdio.h>
+#include<stdlib.h>
 
+typedef struct node{
+    int data;
+    struct node* next;
+}Node;
 
-typedef int element;
-typedef struct queue *queueptr;
+Node* front = NULL;
+Node* rear = NULL;
 
+void enqueue(int value)
+{   
+    Node* newnode = (Node*)malloc(sizeof(Node));
 
-typedef struct queue {
-    element item;
-    queueptr link;
-} queue;
-
-
-queueptr front = NULL;
-queueptr rear = NULL;
-
-int ISEMPTY();
-void addq(element item);
-element deleteq();
-void display();
-
-
-int main() {
-    int choice, item;
-
-    while (1) {
-        printf("\n--- Single Queue Menu ---\n");
-        printf("1. Add to Queue\n");
-        printf("2. Delete from Queue\n");
-        printf("3. Display Queue\n");
-        printf("4. Exit\n");
-        printf("Enter your choice: ");
-
-        scanf("%d", &choice);
-
-
-        switch (choice) {
-            case 1:
-                printf("Enter item to add: ");
-                scanf("%d", &item);
-                addq(item);
-                printf("Item %d added to queue.\n", item);
-                break;
-
-            case 2:
-
-                item = deleteq();
-                printf("Deleted item %d from queue.\n", item);
-                break;
-
-            case 3:
-                display();
-                break;
-
-            case 4:
-                printf("Exiting program.\n");
-                exit(0);
-
-            default:
-                printf("Invalid choice. Please try again.\n");
-        }
-    }
-
-    return 0;
-}
-
-int ISEMPTY() {
-    return (front == NULL);
-}
-
-
-void addq(element item) {
-
-    queueptr temp = (queueptr)malloc(sizeof(queue));
-
-
-    if (temp == NULL) {
-        fprintf(stderr, "Memory allocation failed. The queue is full!\n");
+    if(!newnode){
+        fprintf(stderr, "Memory allocation failed\n");
         exit(1);
     }
 
-    temp->item = item;
-    temp->link = NULL;
+    newnode->data = value;
+    newnode->next = NULL;
 
-    if (ISEMPTY()) {
-        front = temp;
-    } else {
-        rear->link = temp;
+    if(front == NULL){
+        rear = front = newnode;
+    }else{
+        rear->next = newnode;
+        rear = newnode;
     }
-    rear = temp;
+    printf("added %d onto rear\n", value);
+
+
 }
 
-
-element deleteq() {
-    queueptr temp = front;
-    element item;
-
-    if (ISEMPTY()) {
-        fprintf(stderr, "The queue is empty, cannot delete.\n");
-        exit(1);
+int dequeue(){
+    Node* temp = front;
+    int item;
+    if(front == NULL){
+        printf("stack is empty");
+        return -1;
     }
-
-    item = temp->item;
-    front = temp->link;
+    item = temp->data;
+    front = front->next;
     free(temp);
-    if (ISEMPTY()) {
+
+    if(front== NULL){
         rear = NULL;
     }
     return item;
 }
 
-
-void display() {
-    queueptr temp = front;
-
-    if (ISEMPTY()) {
-        printf("Queue is empty.\n");
+void display(){
+    Node* temp = front;
+    if(front == NULL){
+        printf("Stack is empty");
         return;
     }
 
-    printf("Queue contents (front to rear): ");
-    while (temp != NULL) {
-        printf("%d ", temp->item);
-        temp = temp->link;
+    while(temp!=NULL){
+        printf("%d->",temp->data);
+        temp = temp->next;
+
     }
-    printf("\n");
+    printf("NULL\n");
+}
+int main(){
+    int choice,value;
+    while(1){
+        printf("\n---queue menu---");
+        printf("\n1. enqueue");
+        printf("\n2. dequeue");
+        printf("\n3. display");
+        printf("\n4. exit");
+        printf("\nEnter your choice: ");
+        scanf("%d", &choice);
+
+        switch(choice){
+            case 1: printf("Enter item to be added: ");
+                    scanf("%d", &value);
+                    enqueue(value);
+                    break;
+            case 2: value = dequeue();
+                    if(value!=-1)
+                    printf("popped %d", value);
+                    break;
+            case 3: display();
+                    break;
+            case 4: printf("exiting\n");
+                    exit(0);
+            default: 
+                    printf("enter valid choice bruh");
+
+
+        }
+
+    }
+    return 0;
 }