write a program in c to implement circular queue using array
Answers
/*static circular queue*/
#include <stdio.h>
#define size 5
void insertq(int[], int);
void deleteq(int[]);
void display(int[]);
int front = - 1;
int rear = - 1;
int main()
{
int n, ch;
int queue[size];
do
{
printf("\n\n Circular Queue:\n1. Insert \n2. Delete\n3. Display\n0. Exit");
printf("\nEnter Choice 0-3? : ");
scanf("%d", &ch);
switch (ch)
{
case 1:
printf("\nEnter number: ");
scanf("%d", &n);
insertq(queue, n);
break;
case 2:
deleteq(queue);
break;
case 3:
display(queue);
break;
}
}while (ch != 0);
}
void insertq(int queue[], int item)
{
if ((front == 0 && rear == size - 1) || (front == rear + 1))
{
printf("queue is full");
return;
}
else if (rear == - 1)
{
rear++;
front++;
}
else if (rear == size - 1 && front > 0)
{
rear = 0;
}
else
{
rear++;
}
queue[rear] = item;
}
void display(int queue[])
{
int i;
printf("\n");
if (front > rear)
{
for (i = front; i < size; i++)
{
printf("%d ", queue[i]);
}
for (i = 0; i <= rear; i++)
printf("%d ", queue[i]);
}
else
{
for (i = front; i <= rear; i++)
printf("%d ", queue[i]);
}
}
void deleteq(int queue[])
{
if (front == - 1)
{
printf("Queue is empty ");
}
else if (front == rear)
{
printf("\n %d deleted", queue[front]);
front = - 1;
rear = - 1;
}
else
{
printf("\n %d deleted", queue[front]);
front++;
}
}