C-programming/CircularQueue.c at main · nabeel-w/C-programming · 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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
#include<stdio.h>
#include<stdlib.h>
#include<limits.h>

typedef struct queue
{
    int* arr;
    unsigned cap;
    int rear;
    int front;
}queue;
queue* create_queue(unsigned cap)
{
    int size=(cap)*sizeof(int);
    queue* que=malloc(sizeof(queue));
    que->arr=(int*)malloc(size);
    que->cap=cap;
    que->front=-1;
    que->rear=-1;
    return que;
}
void enque(queue* que)
{
     if ((que->front == 0 && que->rear == que->cap-1) ||(que->rear == (que->front-1)%(que->cap-1)))
    {
        printf("\nQueue is Full\n");
        return;
    }
    else if(que->front==-1)
    {
        que->front=que->rear=0;
        printf("Enter Element: ");
        scanf("%d",&que->arr[que->rear]);
    }
    else if(que->rear==que->cap-1&&que->front!=0)
    {
        que->rear=0;
        printf("Enter Element: ");
        scanf("%d",&que->arr[que->rear]);
    }
    else
    {
        printf("Enter Element: ");
        scanf("%d",&que->arr[++que->rear]);
    }
}
int deque(queue* que)
{
    if(que->front==-1)
    {
        printf("Queue is Empty!\n");
        return INT_MIN;
    }
    int data = que->arr[que->front];
    que->arr[que->front] = -1;
    if (que->front == que->rear)
    {
        que->front = -1;
        que->rear = -1;
    }
    else if (que->front == que->cap-1)
    {
        que->front = 0;
    }
    else
    {
        que->front++;
    }
    return data;
}
int peek(queue* que)
{
    if(que->front!=-1)
        return(que->arr[que->front]);
    else
    {
        printf("Queue empty\n");
        return INT_MIN;
    }
}
void display(queue* que)
{
    if(que->front==-1)
    {
        printf("Queue is Empty!\n");
        return ;
    }
    printf("\nElements in Circular Queue are: ");
    if(que->rear>=que->front)
    {
        for(int i=que->front;i<=que->rear;i++)
        {
            printf("%d  ",que->arr[i]);
        }
    }
    else
    {
        for(int i=que->front;i<que->cap;i++)
        {
            printf("%d  ",que->arr[i]);
        }
        for(int i=0;i<=que->rear;i++)
        {
            printf("%d  ",que->arr[i]);
        }
    }
    printf("\n");
}

int main(void)
{
    int ch;
    queue* que=create_queue(5);
     while (1)
    {
        printf("1.Enqueue Operation\n");
        printf("2.Dequeue Operation\n");
        printf("3.Display the Queue\n");
        printf("4.Peek Queue\n");
        printf("5.Exit\n");
        printf("Enter your choice of operations : ");
        scanf("%d", &ch);
        switch (ch)
        {
            case 1:
            enque(que);
            break;
            case 2:
            printf("Element dequeued: %d\n",deque(que));
            break;
            case 3:
            display(que);
            break;
            case 4:
            printf("Element at front:%d\n",peek(que));
            break;
            case 5:
            exit(0);
            break;
            default:
            printf("Wrong Choice\n");
        }
    }
}