C++

Forum

 
Need some help

andersonwq (25)
I am losing data. somewhere and im not sure where. I am pretty sure it is in the pushqueue function.....it is suppose to put the symbols in order by its priority.
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
 
#include <iomanip>
#include <iostream>
#include <typeinfo>
#include <cstdlib>
#include <string>

using namespace std;

// Specification file for a linked list abstract data type class.
// This linked list is actually a stack, since all additions and
// removals are at the head.
template<class type>
struct node // Each node has two fields:
{
        type data; // a data field,
        node<type> *next; // and a pointer field.
        type priority;
};

template<class type>
class stack
{
        private:
                node<type> *head; // Pointer to the first cell.

        public:

                stack();
                void push(type item);
                void pushprior(type item, type priority);
                type pop();
                void view();
                void pushqueue(type item, type priority);
};

template<class type>
stack<type>::stack()
{
        head=NULL;
}

template<class type>
void stack<type> :: push (type item)
{
        node<type> *t = new node<type>;
 t -> data = item;
        t -> next = head;
        head = t;

}
//adds the int into the list and then sorts it to where it should be located
template<class type>
void stack<type>::pushqueue (type item,type priorityt)
{
        node<type> *t = new node<type>;
        node<type> *tmp = new node<type>;
        node<type> *trail = new node<type>;
        //trail = NULL;

        if(head == NULL) //Startig the list
        {
                t-> data = item;
                t->priority=priorityt;
                t -> next = head;
                head = t;
        }
        else if(head != NULL)
        {
                t = head;
                while(t != NULL && priorityt > t->priority){ //Puts inside the list
                trail = t;
                t = t->next;
                }
        tmp->data = item;
        tmp->priority=priorityt;
        tmp->next = t;
        trail->next = tmp;
        }
}
// Function to remove the first element from the stack and
// return it to the caller.
template<class type>
type stack<type> :: pop ()
{

        node<type>* cur;
        cur = head;
        if(cur == NULL)
        {
                cout<<"Nothing to pop"<<endl;;
}

        else
        {
                head = cur -> next;
                return cur->data;
                delete cur;
        }
}
// Accessor functions.
// Function to see whether an element is on the list.
template<class type>
void stack<type> :: view ()
{
        node<type>* tmp = head;

        while(tmp != NULL){
                cout << tmp -> data;
                tmp = tmp -> next;
                cout<<endl;
        }
        cout<<endl;
}

int main()
{

stack<char> b;
stack<int> c;

b.pushqueue('6',3);
cout<<endl;
b.pushqueue('@',4);
cout<<endl;
b.pushqueue('b',2);

b.view();
}

Last edited on
andersonwq (25)
its a priority queue
Zhuge (4664)
You definitely have memory leaks in pushqueue(). It doesn't look like you are losing any data from the list, however...

If head is NULL, tmp and trail both leak memory, as they are never used and not deleted.

If it isn't, t and trail leak as you assign them away from the new nodes you created at the functions beginning.
Topic archived. No new replies allowed.