Program: Implement a Queue using Array

#include <stdio.h>

/*
* C Program to Implement a Queue using an Array
*/

#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 {
printf("%d ", queue_array[i]);
}

printf("\n");

}

} /*End of display() */

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