Added stack code

C/CircularQueue.c

@@ -0,0 +1,114 @@
+// Circular Queue implementation in C
+
+#include <stdio.h>
+
+#define SIZE 5
+
+int items[SIZE];
+int front = -1, rear = -1;
+
+// Check if the queue is full
+int isFull()
+{
+    if ((front == rear + 1) || (front == 0 && rear == SIZE - 1))
+        return 1;
+    return 0;
+}
+
+// Check if the queue is empty
+int isEmpty()
+{
+    if (front == -1)
+        return 1;
+    return 0;
+}
+
+// Adding an element
+void enQueue(int element)
+{
+    if (isFull())
+        printf("\n Queue is full!! \n");
+    else
+    {
+        if (front == -1)
+            front = 0;
+        rear = (rear + 1) % SIZE;
+        items[rear] = element;
+        printf("\n Inserted -> %d", element);
+    }
+}
+
+// Removing an element
+int deQueue()
+{
+    int element;
+    if (isEmpty())
+    {
+        printf("\n Queue is empty !! \n");
+        return (-1);
+    }
+    else
+    {
+        element = items[front];
+        if (front == rear)
+        {
+            front = -1;
+            rear = -1;
+        }
+        // Q has only one element, so we reset the
+        // queue after dequeing it. ?
+        else
+        {
+            front = (front + 1) % SIZE;
+        }
+        printf("\n Deleted element -> %d \n", element);
+        return (element);
+    }
+}
+
+// Display the queue
+void display()
+{
+    int i;
+    if (isEmpty())
+        printf(" \n Empty Queue\n");
+    else
+    {
+        printf("\n Front -> %d ", front);
+        printf("\n Items -> ");
+        for (i = front; i != rear; i = (i + 1) % SIZE)
+        {
+            printf("%d ", items[i]);
+        }
+        printf("%d ", items[i]);
+        printf("\n Rear -> %d \n", rear);
+    }
+}
+
+int main()
+{
+    // Fails because front = -1
+    deQueue();
+
+    enQueue(1);
+    enQueue(2);
+    enQueue(3);
+    enQueue(4);
+    enQueue(5);
+
+    // Fails to enqueue because front == 0 && rear == SIZE - 1
+    enQueue(6);
+
+    display();
+    deQueue();
+
+    display();
+
+    enQueue(7);
+    display();
+
+    // Fails to enqueue because front == rear + 1
+    enQueue(8);
+
+    return 0;
+}

C/Stack.c

@@ -0,0 +1,153 @@
+#include <stdio.h>
+#include <stdlib.h>
+#define N 10
+int stack[N];
+
+int top = -1;
+
+void push()
+{
+
+    int x;
+
+    printf("Enter the Data: \n");
+
+    scanf("%d", &x);
+
+    if (top == N - 1)
+
+    {
+
+        printf("Stack Overflow\n");
+    }
+
+    else
+
+    {
+
+        top++;
+
+        stack[top] = x;
+    }
+}
+
+void pop()
+{
+
+    int item;
+
+    if (top == -1)
+
+    {
+
+        printf("Stack Underflow\n");
+    }
+
+    else
+
+    {
+
+        item = stack[top];
+
+        top--;
+
+        printf("The popped element is %d: \n", item);
+    }
+}
+
+void display()
+{
+
+    int i;
+
+    for (i = top; i >= 0; i++)
+
+    {
+
+        printf("%d \n", stack[i]);
+    }
+}
+
+void peek()
+{
+
+    if (top == -1)
+
+    {
+
+        printf("Stack is Empty\n");
+    }
+
+    else
+
+    {
+
+        printf("The top element is: %d\n", stack[top]);
+    }
+}
+
+void main()
+{
+
+    int choice;
+
+    printf("Enter your Choice: \n0:Exit\n1:Push\n2:Pop\n3:Peek\n4:Display\n");
+
+    do
+
+    {
+
+        scanf("%d", &choice);
+
+        switch (choice)
+
+        {
+
+        case 1:
+
+        {
+
+            push();
+
+            break;
+        }
+
+        case 2:
+
+        {
+
+            pop();
+
+            break;
+        }
+
+        case 3:
+
+        {
+
+            peek();
+
+            break;
+        }
+
+        case 4:
+
+        {
+
+            display();
+
+            break;
+        }
+
+        default:
+
+        {
+
+            printf("Invalid Choice\n");
+
+            break;
+        }
+        }
+
+    } while (choice != 0);
+}