From 2d0d37bb2a1f096dd35b8e50d324165d9517a501 Mon Sep 17 00:00:00 2001
From: Shriya Dindi <126611334+shriyadindi@users.noreply.github.com>
Date: Sun, 10 Nov 2024 09:12:47 +0530
Subject: [PATCH] Create StackQueue.c

---
 .../TwoStackstoImplementQueue/StackQueue.c    | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 StackQueues/TwoStackstoImplementQueue/StackQueue.c

diff --git a/StackQueues/TwoStackstoImplementQueue/StackQueue.c b/StackQueues/TwoStackstoImplementQueue/StackQueue.c
new file mode 100644
index 00000000..47e8889b
--- /dev/null
+++ b/StackQueues/TwoStackstoImplementQueue/StackQueue.c
@@ -0,0 +1,98 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX 100
+
+// Stack structure with top pointer and array for elements
+typedef struct Stack {
+    int arr[MAX];
+    int top;
+} Stack;
+
+// Function to initialize a stack
+void initStack(Stack *stack) {
+    stack->top = -1;
+}
+
+// Function to check if a stack is empty
+int isEmpty(Stack *stack) {
+    return stack->top == -1;
+}
+
+// Function to check if a stack is full
+int isFull(Stack *stack) {
+    return stack->top == MAX - 1;
+}
+
+// Function to push an element onto a stack
+void push(Stack *stack, int data) {
+    if (isFull(stack)) {
+        printf("Stack overflow\n");
+        return;
+    }
+    stack->arr[++stack->top] = data;
+}
+
+// Function to pop an element from a stack
+int pop(Stack *stack) {
+    if (isEmpty(stack)) {
+        printf("Stack underflow\n");
+        return -1;
+    }
+    return stack->arr[stack->top--];
+}
+
+// Queue structure using two stacks
+typedef struct QueueUsingStacks {
+    Stack stack1;
+    Stack stack2;
+} QueueUsingStacks;
+
+// Function to initialize the queue
+void initQueue(QueueUsingStacks *queue) {
+    initStack(&queue->stack1);
+    initStack(&queue->stack2);
+}
+
+// Enqueue operation
+void enqueue(QueueUsingStacks *queue, int data) {
+    push(&queue->stack1, data);
+    printf("Enqueued %d\n", data);
+}
+
+// Dequeue operation
+int dequeue(QueueUsingStacks *queue) {
+    // If both stacks are empty, queue is empty
+    if (isEmpty(&queue->stack1) && isEmpty(&queue->stack2)) {
+        printf("Queue is empty\n");
+        return -1;
+    }
+
+    // Move elements from stack1 to stack2 if stack2 is empty
+    if (isEmpty(&queue->stack2)) {
+        while (!isEmpty(&queue->stack1)) {
+            push(&queue->stack2, pop(&queue->stack1));
+        }
+    }
+
+    // Pop from stack2, which is the front of the queue
+    int dequeuedValue = pop(&queue->stack2);
+    printf("Dequeued %d\n", dequeuedValue);
+    return dequeuedValue;
+}
+
+int main() {
+    QueueUsingStacks queue;
+    initQueue(&queue);
+
+    enqueue(&queue, 1);
+    enqueue(&queue, 2);
+    enqueue(&queue, 3);
+
+    dequeue(&queue);
+    dequeue(&queue);
+    dequeue(&queue);
+    dequeue(&queue);  // Queue is empty at this point
+
+    return 0;
+}