rest of the codes

CircQueue.c

@@ -0,0 +1,124 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+#define MALLOC(x,size,type) (x = (type*)malloc((size) * sizeof(type)))
+
+typedef struct
+{
+    int n;
+} element;
+
+int front = 0, rear = 0, capacity;
+element *queue;
+
+void copy(element* start, element* end, element* newQueue)
+{
+    element* j;
+    element* i;
+    i = newQueue;
+    j = start;
+    for (; j < end; j++, i++)
+    {
+        *i = *j;
+    }
+}
+
+void queueFull()
+{
+    element* newQueue;
+    MALLOC(newQueue, capacity * 2, element);
+    int start = (front + 1) % capacity;
+
+    if (start < 2) // either 1 or 0, 1 when front at 0, 0 when front at capacity - 1
+        copy(queue + start, queue + start + capacity - 1, newQueue);
+    else
+    {
+        copy(queue + start, queue + capacity, newQueue);
+        copy(queue, queue + rear + 1, newQueue + capacity - start);
+    }
+
+    front = 2 * capacity - 1;
+    rear = capacity - 1;
+    capacity *= 2;
+    free(queue);
+    queue = newQueue;
+}
+
+void addq(element item)
+{
+    rear = (rear + 1) % capacity;
+    if (front == rear)
+        queueFull();
+    queue[rear] = item;
+}
+
+element deleteq()
+{
+    element item;
+    if (front == rear)
+    {
+        item.n = -1;
+        return item;
+    }
+    front = (front + 1) % capacity;
+    return queue[front];
+}
+
+void displayq()
+{
+    int i;
+    if (front == rear)
+    {
+        printf("Queue Empty\n");
+        return;
+    }
+    for (i = (front + 1) % capacity; i != rear; i = (i + 1) % capacity)
+        printf("%d\t", queue[i].n);
+    printf("%d\n", queue[i].n);
+    // printf("Front: %d Rear: %d\n", front, rear);
+}
+
+int main()
+{
+    int choice;
+    element item;
+
+    printf("Enter initial size: ");
+    scanf("%d", &capacity);
+    MALLOC(queue, capacity, element);
+
+    while (1)
+    {
+        printf("\n1. Add\n2. Delete\n3. Display\n4. Exit\n");
+        scanf("%d", &choice);
+
+        switch (choice)
+        {
+        case 1:
+            printf("Enter item to add: ");
+            scanf("%d", &item.n);
+            addq(item);
+            break;
+
+        case 2:
+            item = deleteq();
+            if (item.n == -1)
+                printf("Queue Empty\n");
+            else
+                printf("Item deleted: %d\n", item.n);
+            break;
+
+        case 3:
+            displayq();
+            break;
+
+        case 4:
+            exit(0);
+
+        default:
+            printf("Invalid choice\n");
+        }
+    }
+
+    return 0;
+}