C-programs/double_endede_queue_correct.c at main · Kumaraditya18027/C-programs · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
#include<stdio.h>
#include<stdlib.h>
typedef struct queue
{
    int f;int r;int *a;int n;
}qu;
void enqueue_fr(qu *q,int x)
{
    if((q->f==0&&q->r==q->n-1)||(q->f==q->r+1))
    {
        printf("queue is full\n");
    }
    else if(q->f==-1&&q->r==-1)
    {
        q->f=q->r=0;
        q->a[q->f]=x;
    }
    else if(q->f==0)
    {
        q->f=q->n-1;
        q->a[q->f]=x;
    }
    else
    {
        q->f--;
        q->a[q->f]=x;
    }
}
void enqueue_re(qu *q,int x)
{
    if((q->f==0&&q->r==q->n-1)||(q->f==q->r+1))
    printf("queue is full");
    else if(q->f==-1&&q->r==-1)
    {
        q->f=q->r=0;
        q->a[q->r]=x;
    }
    else if(q->r==q->n-1)
    {
        q->r=0;
        q->a[q->r]=x;
    }
    else
    {
        q->r++;
        q->a[q->r]=x;
    }
}
void dequeue_fr(qu *q)
{
    if(q->f==-1&&q->r==-1)
    printf("queue is empty\n");
    else if(q->r==q->f)//only one element present in queue(array).
    {
        printf("the deleted element is %d\n",q->a[q->f]);
        q->f=q->r=-1;
    }
    else if(q->f=q->n-1)
    {
        printf("%d \n",q->a[q->f]);
        q->f=0;
    }
    else
    {
         printf("%d \n",q->a[q->f]);
         q->f++;
    }
}
void dequeue_rr(qu *q)
{
    if(q->f==-1&&q->r==-1)
    printf("queue is empty\n");
    else if(q->r==q->f)
    {
        printf("%d \n",q->a[q->r]);
        q->r=q->f=-1;
    }
    else if(q->r==0)
    {
        printf("%d \n",q->a[q->r]);
        q->r=q->n-1;
    }
    else
    {
        printf("%d \n",q->a[q->r]);
        q->r--;
    }

}
void display(qu q)
{
    int i=q.f;
    while(i!=q.r)
    {
        printf("%d ",q.a[i]);
        i=(i+1)%q.n;
    }
    printf("%d ",q.a[q.r]);
}
void main()
{
    qu q;
    int n;
    scanf("%d",&q.n);
    q.a=(int*)malloc(sizeof(int)*q.n);
    q.f=q.r=-1;
    enqueue_fr(&q,2);
    enqueue_fr(&q,5);
    enqueue_fr(&q,7);
    enqueue_re(&q,3);
    enqueue_re(&q,1);
    dequeue_rr(&q);
    dequeue_fr(&q);
    display(q);
}