Write a Program to implementation of Circular Queue in C

 

Write a Program to implementation of Circular Queue in C

# include<stdio.h> # define MAX 3   int cqueue_arr[MAX]; int front = -1; int rear = -1;   /*Begin of insert*/ void insert(int item) {        if((front == 0 && rear == MAX-1) || (front == rear+1))        {               printf("Queue Overflow \n");               return;        }        if (front == -1)  /*If queue is empty */        {               front = 0;               rear = 0;        }        else        {               if(rear == MAX-1)  /*rear is at last position of queue */                      rear = 0;               else                      rear = rear+1;        }        cqueue_arr[rear] = item ; } /*End of insert*/   /*Begin of del*/ void del() {        if (front == -1)        {               printf("Queue Underflow\n");               return ;        }        printf("Element deleted from queue is : %d\n",cqueue_arr[front]);        if(front == rear) /* queue has only one element */        {               front = -1;               rear=-1;        }        else        {                   if(front == MAX-1)                      front = 0;               else                      front = front+1;        } } /*End of del() */   /*Begin of display*/ void display() {        int front_pos = front,rear_pos = rear;        if(front == -1)        {               printf("Queue is empty\n");               return;        }        printf("Queue elements :\n");        if( front_pos <= rear_pos )               while(front_pos <= rear_pos)               {                      printf("%d ",cqueue_arr[front_pos]);                      front_pos++;               }        else        {               while(front_pos <= MAX-1)               {                      printf("%d ",cqueue_arr[front_pos]);                      front_pos++;               }               front_pos = 0;               while(front_pos <= rear_pos)               {                      printf("%d ",cqueue_arr[front_pos]);                      front_pos++;               }        }        printf("\n"); } /*End of display*/   /*Begin of main*/ int main() {        int choice,item;        do        {               printf("1.Insert\n");               printf("2.Delete\n");               printf("3.Display\n");               printf("4.Quit\n");                 printf("Enter your choice : ");               scanf("%d",&choice);                 switch(choice)               {                      case 1 :                            printf("Input the element for insertion in queue : ");                            scanf("%d", &item);                              insert(item);                            break;                      case 2 :                            del();                            break;                      case 3:                            display();                            break;                      case 4:                            break;                            default:                            printf("Wrong choice\n");               }        }while(choice!=4);               return 0; } /*End of main*/

Output

1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 1 Input the element for insertion in queue : 23 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 1 Input the element for insertion in queue : 24 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 1 Input the element for insertion in queue : 25 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 1 Input the element for insertion in queue : 56 Queue Overflow 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 3 Queue elements : 23 24 25 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 2 Element deleted from queue is : 23 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 1 Input the element for insertion in queue : 26 1.Insert 2.Delete 3.Display 4.Quit Enter your choice : 3 Queue elements : 24 25 26 1.Insert 2.Delete 3.Display 4.Quit Enter your choice :