8.C Program to implement a simple queue (Part B)

 C Program to implement a simple queue(Part B)

ALGORITHM :

Step 1: Start

Step 2: Define a constant MAX_SIZE to represent the maximum size of the queue.

Step 3: Declare a queue structure with necessary variables (e.g., front and rear to keep track of the front and rear of the queue, and an array to store elements).

Step 4: Implement the enqueue function to add an item to the rear of the queue.

        a. Check if the queue is full (rear == MAX_SIZE - 1).

        b. If not full, increment rear by 1 and add the item to the queue.

        c. If the queue is full, display an overflow error message.

Step 5: Implement the dequeue function to remove and return the front item from the queue.

        a. Check if the queue is empty (front == rear).

        b. If not empty, remove the front item from the queue, increment front by 1, and return the item.

        c. If the queue is empty, display an underflow error message or return a special value to indicate the queue is empty (e.g., -1).

Step 6: Implement the peek function to get the front item from the queue without removing it.

        a. Check if the queue is empty (front == rear).

        b. If not empty, return the front item from the queue.

        c. If the queue is empty, display an error message or return a special value to indicate the queue is empty (e.g., -1).

Step 7: Implement the is_empty function to check if the queue is empty.

        a. Check if the queue is empty (front == rear).

        b. If empty, return 1 (true); otherwise, return 0 (false).

Step 8: Implement the is_full function to check if the queue is full.

        a. Check if the queue is full (rear == MAX_SIZE - 1).

        b. If full, return 1 (true); otherwise, return 0 (false).

Step 9: End

SOURCE CODE :

#include<stdio.h>
#include<time.h>
#define  max 50
void insert();
void delete();
void display();
int queue_array[max];
int rear=-1;
int front=-1;
void main()
{
int choice;
clock_t start,end;
  double cpu_time_used;
clrscr();
start = clock();
while(1)
{
printf("1. insert \n");
printf("2. delete \n");
printf("3.display  \n");
printf("4.exit\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 = clock();
            cpu_time_used=((double)(end-start))/CLOCKS_PER_SEC;
      printf("the time taken for execution is %f seconds",cpu_time_used);
      getch();
  }
  }
void insert()
{
int add_item;
if(rear==max-1)
printf("queue is overflow \n");
else
{
if (front==-1)
front=0;
printf("insert the element in queue");
scanf("%d",&add_item);
rear=rear+1;
queue_array[rear]=add_item;
}
}
void 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;
}
}
void 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");
}
}

OUTPUT :ll update soon