queue array code in c code example
Example: dequeue operations using static array
# include<stdio.h>
# define MAX 5
int deque_arr[MAX];
int left = -1;
int right = -1;
/*Begin of insert_right*/
void insert_right()
{
int added_item;
if((left == 0 && right == MAX-1) || (left == right+1))
{ printf("Queue Overflow\n");
return;}
if (left == -1) /* if queue is initially empty */
{ left = 0;
right = 0;}
else
if(right == MAX-1) /*right is at last position of queue */
right = 0;
else
right = right+1;
printf("Input the element for adding in queue : ");
scanf("%d", &added_item);
deque_arr[right] = added_item ;
}
/*End of insert_right*/
/*Begin of insert_left*/
void insert_left()
{ int added_item;
if((left == 0 && right == MAX-1) || (left == right+1))
{ printf("Queue Overflow \n");
return; }
if (left == -1)/*If queue is initially empty*/
{ left = 0;
right = 0; }
else
if(left== 0)
left=MAX-1;
else
left=left-1;
printf("Input the element for adding in queue : ");
scanf("%d", &added_item);
deque_arr[left] = added_item ; }
/*End of insert_left*/
/*Begin of delete_left*/
void delete_left()
{ if (left == -1)
{ printf("Queue Underflow\n");
return ; }
printf("Element deleted from queue is : %d\n",deque_arr[left]);
if(left == right) /*Queue has only one element */
{ left = -1;
right=-1; }
else
if(left == MAX-1)
left = 0;
else
left = left+1;
}
/*End of delete_left*/
/*Begin of delete_right*/
void delete_right()
{if (left == -1)
{printf("Queue Underflow\n");
return ; }
printf("Element deleted from queue is : %d\n",deque_arr[right]);
if(left == right) /*queue has only one element*/
{ left = -1;
right=-1; }
else
if(right == 0)
right=MAX-1;
else
right=right-1; }
/*End of delete_right*/
/*Begin of input_que*/
void display_queue()
{ int front_pos = left,rear_pos = right;
if(left == -1)
{ printf("Queue is empty\n");
return; }
printf("Queue elements :\n");
if( front_pos <= rear_pos )
{ while(front_pos <= rear_pos)
{ printf("%d ",deque_arr[front_pos]);
front_pos++; } }
else
{ while(front_pos <= MAX-1)
{ printf("%d ",deque_arr[front_pos]);
front_pos++; }
front_pos = 0;
while(front_pos <= rear_pos)
{ printf("%d ",deque_arr[front_pos]);
front_pos++;
}
}
printf("\n");
}
/*End of display_queue*/
/*Begin of input_que*/
void input_que()
{ int choice;
do
{ printf("1.Insert at right\n");
printf("2.Delete from left\n");
printf("3.Delete from right\n");
printf("4.Display\n");
printf("5.Quit\n");
printf("Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{ case 1:
insert_right();
break;
case 2:
delete_left();
break;
case 3:
delete_right();
break;
case 4:
display_queue();
break;
case 5:
break;
default:
printf("Wrong choice\n");
}
}while(choice!=5);
}
/*End of input_que*/
/*Begin of output_que*/
void output_que()
{ int choice;
do
{ printf("1.Insert at right\n");
printf("2.Insert at left\n");
printf("3.Delete from left\n");
printf("4.Display\n");
printf("5.Quit\n");
printf("Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1:
insert_right();
break;
case 2:
insert_left();
break;
case 3:
delete_left();
break;
case 4:
display_queue();
break;
case 5:
break;
default:
printf("Wrong choice\n");
}
}while(choice!=5);
}
/*End of output_que*/
/*Begin of main*/
main()
{ int choice;
printf("1.Input restricted dequeue\n");
printf("2.Output restricted dequeue\n");
printf("Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1 :
input_que();
break;
case 2:
output_que();
break;
default:
printf("Wrong choice\n");
}
}
/*End of main*/