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January 23rd, 2012, 09:06 AM  #1 
Joined: Jan 2012 Posts: 2  Question about linked list
I'm learning Linked lists and i'm having trouble adding numbers to the back of the list. I can only add up to two, for example: 1, 2, then, if i add a third number, it will replace the second. example: 1, 3, What am i doing wrong? Code: #include <iostream> #include <conio.h> using namespace std; class list { private: struct node { int data; node *next; }*head; public: list() : head(NULL) {} ~list(); void push_back(int &d); void print() const; }; list::~list() { node *temp = head; node *tmp2; while(temp != NULL) { tmp2 = temp; temp = temp>next; delete tmp2; } cout << "All nodes destroyed..." << endl; } void list::push_back(int &d) { if(head == NULL) { head = new node; head>data = d; head>next = NULL; } else { node *temp = head; node *t; t = new node; t>data = d; t>next = NULL; temp>next = t; } } void list::print() const { if(head == NULL) { cout << "list is empty..." << endl; _getch(); } else { node *temp = head; while(temp != NULL) { cout << temp>data << ' '; temp = temp>next; } } cout << endl << endl; } int main() { list ll; int num; int choice; do { cout << "Enter choice:" << endl; cout << "1. push_back." << endl; cout << "2. print list." << endl; cout << "3. Quit. " <<endl; cout << ">> "; cin >> choice; switch(choice) { case 1: cout << "Enter number: "; cin >> num; cout << endl; ll.push_back(num); num = 0; break; case 2: ll.print(); break; case 3: break; } }while(choice != 3); _getch(); return 0; } 
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February 16th, 2012, 05:49 AM  #2 
Joined: Feb 2012 Posts: 1  Re: Question about linked list
Hi A really simple way to do this is like this: void list:ush_back(const int &d) { node* newNode = new node; newNode>data = d; newNode>next = head; head = newNode; } Note some changes. Parameter is const which means you can do this for example: list ll; ll.push_back(1); What happens is that head is always the last element added to the list. It is behaving like a stack. If this behaviour is fine for your application then this is the simplest implementation. Angus 

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