Codes_of_data_stractures_using_cpp/queue_useing_array.cpp at main · sadikmahmudadive/Codes_of_data_stractures_using_cpp · 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
#include<iostream>
#define size_of_arr 20

using namespace std;

class queue
{
    int* arr;
    int front;
    int back;

    public:
    queue()
    {
        arr = new int[size_of_arr];
        front =-1;
        back =-1;
    }

    void push(int x)
    {
        if(back == size_of_arr-1)
        {
            cout << "Queue is Overflow" <<endl;
            return;
        }
        back++;
        arr[back]=x;

        if(front == -1)
        {
            front++;
        }
    }

    void pop()
    {
        if(front == -1 || front>back)
        {
            cout << "No elements in Queue" << endl;
            return;
        }

        front++;
    }

    int peek()
    {
        if(front == -1 || front>back)
        {
            cout << "No elements in Queue" << endl;
            return -1;
        }
        return arr[front];
    }

    bool empty()
    {
        if(front == -1 || front>back)
        {
            //cout << "No elements in Queue" << endl;
            return true;
        }
        return false;
    }
};

int main()
{
    queue q;

    q.push(1);
    q.push(2);
    q.push(3);
    q.push(4);

    cout << q.peek() << endl;
    q.pop();

    cout << q.peek() << endl;
    q.pop();

    cout << q.peek() << endl;
    q.pop();

    cout << q.peek() << endl;
    q.pop();

    cout << q.empty() << endl;

    return 0;
}