Added Queue implementation DS in C

C/Queue.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <limits.h>
+#include <stdbool.h>
+#define capacity 5
+typedef struct queue
+{
+    int data[capacity];
+    int front;
+    int rear;
+    int current_size;
+} queue;
+void initialise(queue *q)
+{
+    q->front = -1;
+    q->rear = -1;
+    q->current_size=0;
+}
+bool empty(queue *q)
+{
+    return (q->front == -1 && q->rear == -1);
+    //can also use currentsize==0
+}
+bool full(queue *q)
+{
+    return (q->front == (q->rear + 1) % capacity);
+    //can also use currentsize==capacity
+}
+int enqueue(queue *q, int a)
+{
+    if (full(q))
+        {
+            printf("QUEUE IS FULL\n");
+            return INT_MAX;
+        }
+    if (empty(q))
+        q->front = 0;
+    q->rear = (q->rear + 1) % capacity;
+    q->data[q->rear] = a;
+    q->current_size++;
+    return a;
+}
+int dequeue(queue *q)
+{
+    if (empty(q))
+    {
+        printf("QUEUE IS EMPTY\n");
+        return INT_MIN;
+    }
+    int a = q->data[q->front];
+    q->front = (q->front + 1) % capacity;
+    q->current_size--;
+    if (q->current_size==0)
+        initialise(q);
+    return a;
+}
+int main()
+{
+    queue q1;
+    initialise(&q1);
+    printf("enqueued:%d\n",enqueue(&q1,5));
+    printf("enqueued:%d\n",enqueue(&q1,15));
+    printf("enqueued:%d\n",enqueue(&q1,25));
+    printf("enqueued:%d\n",enqueue(&q1,35));
+    printf("current size = %d\n",q1.current_size);
+    printf("enqueued:%d\n",enqueue(&q1,45));
+    printf("%d\n",enqueue(&q1,55));
+    printf("dequeued:%d\n",dequeue(&q1));
+    printf("dequeued:%d\n",dequeue(&q1));
+    printf("dequeued:%d\n",dequeue(&q1));
+    printf("current size = %d\n",q1.current_size);
+    printf("dequeued:%d\n",dequeue(&q1));
+    printf("dequeued:%d\n",dequeue(&q1));
+    printf("%d\n",dequeue(&q1));
+    printf("enqueued:%d\n",enqueue(&q1,65));
+    printf("enqueued:%d\n\n",enqueue(&q1,75));
+    for (int i = 0; i < q1.current_size; i++)
+    {
+        printf("element %d in queue is %d\n",i+1,q1.data[i]);
+    }
+
+    return 0;
+}
+
+//output is
+/*
+enqueued:5
+enqueued:15
+enqueued:25
+enqueued:35
+current size = 4
+enqueued:45
+QUEUE IS FULL
+2147483647
+dequeued:5
+dequeued:15
+dequeued:25
+current size = 2
+dequeued:35
+dequeued:45
+QUEUE IS EMPTY
+-2147483648
+enqueued:65
+enqueued:75
+
+element 1 in queue is 65
+element 2 in queue is 75
+*/