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Added Double ended queue to C(#126) 

* Added double ended queue using array

* replace space( ) to dash(-)

* remove space complexity 

removed space complexity because i did know how to check space complexity

* done the requested changes

* update queue index readme

add double-ended-queue-using-array.c under c-or-cpp

Co-authored-by: Arsenic <54987647+Arsenic-ATG@users.noreply.github.com>
pull/134/head
Ujjwal 2021-04-03 22:14:38 +05:30 committed by GitHub
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1
queues/README.md
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@ -4,3 +4,4 @@
1. [Queue using linked list](c-or-cpp/queue-linked-list.cpp)
2. [Circular Queue using linked list](c-or-cpp/circular-queue-linked-list.cpp)
3. [Double Ended Queue (using arrays)](c-or-cpp/double-ended-queue-using-array.c)

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queues/c-or-cpp/double-ended-queue-using-array.c 100644
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/* this is a double ended queue implementation using array
means you can insert or delete data from both front and rear */
//included necessary header file
#include<stdio.h>
#include<stdlib.h>
// creating non-primitive named deque using structure concept
struct deque
{
//declaring necessary variable
int front;
int rear;
int capacity;
int *arr;
};
// clear function for different platforms ( currently only windows and unix based os are supported )
void clear_screen()
{
#ifdef _WIN32
system("cls");
#elif __unix__
system("clear");
#else
printf("clear screen not supported\n");
#endif
}
//create deque function mainly give memory to the non-primitive variable deque
struct deque* create_dequeue(int cap)
{
struct deque *array;
// dynamically giving memory
array=(struct deque*)malloc(sizeof(struct deque));
// declaring default value of cap front rear
array->capacity=cap;
array->front=-1;
array->rear=-1;
// dynamically giving memory
array->arr=(int*)malloc(sizeof(int)*cap);
return(array);
}
// insertion front just insert data from front of queue
void insertion_front(struct deque *array,int data)
{
// checking that whether the queue is not full
if(array->rear+1==array->front||array->rear==array->capacity-1&&array->front==0)
printf("queue is full");
//checking is the front equal to -1 means queue is empty or not
else if(array->front==-1)
{
array->front=0;
array->rear=0;
array->arr[array->front]=data;
}
// checking whether the queue has 1 data or not
else if(array->front==0)
{
array->front=array->capacity-1;
array->arr[array->front]=data;
}
// normal condition
else
{
array->front--;
array->arr[array->front]=data;
}
}
// insertion rear basically insert data from end of a queue
void insertion_rear(struct deque *array,int data)
{
//checking is the front equal to -1 means queue is empty or not
if(array->rear==array->capacity-1&&array->front==0||array->rear+1==array->front)
printf("queue is full");
//checking is the rear equal to -1 means queue is empty or not
else if(array->rear==-1)
{
array->rear++;
array->arr[array->rear]=data;
array->front=array->rear;
}
// checking whether queue is full from rear but not from front
else if(array->rear==array->capacity-1&&array->front!=0)
{
array->rear=0;
array->arr[array->rear]=data;
}
// normal condition
else
{
array->rear++;
array->arr[array->rear]=data;
}
}
// deletion front basically delete data from front of queue
void deletion_front(struct deque *array)
{
// queue empty condition
if(array->front==-1)
printf("queue is empty");
else
{
// printing the value which is going to be deleted
printf("deleted value is %d",array->arr[array->front]);
// checking whether the queue has only one data
if(array->front==array->rear)
{
array->front=-1;
array->rear=-1;
}
// checking whether front is equal to capacity-1
else if(array->front==array->capacity-1)
array->front=0;
// normal condition
else
array->front++;
}
}
// deletion rear basically delete data from end of queue
void deletion_rear(struct deque *array)
{
//empty condition
if(array->rear==-1)
printf("queue is empty");
else
{ printf("deleted value is %d",array->arr[array->rear]);
// checking whether the queue has only one data
if(array->rear==array->front)
{
array->front=-1;
array->rear=-1;
}
// checking whether rear is 0 but there not only one data left that means that data are at end of queue
else if(array->rear==0)
array->rear=array->capacity-1;
//normal condition
else
array->rear--;
}
}
// menu basically provide the no. of task can be performed so you can choose one of them
int menu(void)
{
int choice;
printf("\n1: Insertion at Front");
printf("\n2: Insertion at Rear");
printf("\n3: Deletion at Front");
printf("\n4: Deletion at Rear");
printf("\n5: exit");
printf("\n\n enter your choice");
scanf("%d",&choice);
return(choice);
}
// driver code
int main()
{
struct deque *array;
int cap,data;
printf("enter the capacity");
scanf("%d",&cap);
array=create_dequeue(cap);
while(1)
{ clear_screen();
switch(menu())
{
case 1:
printf("enter value");
scanf("%d",&data);
insertion_front(array,data);
break;
case 2:
printf("enter value ");
scanf("%d",&data);
insertion_rear(array,data);
break;
case 3:
deletion_front(array);
break;
case 4:
deletion_rear(array);
break;
case 5:
exit(0);
}
}
return 0;
}
/*
Input: Insert 3 at front
Insert 2 at rear
Insert 5 at rear
Delete from rear
delete from front
Output:
5 had been deleted
3 had been deleted
Time complexity:O(n)
*/