fixes NITSkmOS#56 queue in c

queue/c/queue.c

@@ -0,0 +1,81 @@
+/*
+ * C Program to Implement a Queue using an Array
+ */
+#include <stdio.h>
+
+#define MAX 50
+int queue_array[MAX];
+int rear = - 1;
+int front = - 1;
+main()
+{
+    int choice;
+    while (1)
+    {
+        printf("1.Insert element to queue \n");
+        printf("2.Delete element from queue \n");
+        printf("3.Display all elements of queue \n");
+        printf("4.Quit \n");
+        printf("Enter your choice : ");
+        scanf("%d", &choice);
+        switch (choice)
+        {
+            case 1:
+            insert();
+            break;
+            case 2:
+            delete();
+            break;
+            case 3:
+            display();
+            break;
+            case 4:
+            exit(1);
+            default:
+            printf("Wrong choice \n");
+        } /*End of switch*/
+    } /*End of while*/
+} /*End of main()*/
+insert()
+{
+    int add_item;
+    if (rear == MAX - 1)
+    printf("Queue Overflow \n");
+    else
+    {
+        if (front == - 1)
+        /*If queue is initially empty */
+        front = 0;
+        printf("Inset the element in queue : ");
+        scanf("%d", &add_item);
+        rear = rear + 1;
+        queue_array[rear] = add_item;
+    }
+} /*End of insert()*/
+
+delete()
+{
+    if (front == - 1 || front > rear)
+    {
+        printf("Queue Underflow \n");
+        return ;
+    }
+    else
+    {
+        printf("Element deleted from queue is : %d\n", queue_array[front]);
+        front = front + 1;
+    }
+} /*End of delete() */
+display()
+{
+    int i;
+    if (front == - 1)
+        printf("Queue is empty \n");
+    else
+    {
+        printf("Queue is : \n");
+        for (i = front; i <= rear; i++)
+            printf("%d ", queue_array[i]);
+        printf("\n");
+    }
+} /*End of display() */