Question

Please consider this C++ code for creation and traversing a linked list (number of nodes to be decided by user, not programmer)

#include <iostream>
using namespace std;
class Node
{ 
 public:
 int data; Node* next;
 Node(int d, Node* j): data(d),next(j) {cout << "Constructor\n";}
};

int main()
{int n; Node* p; Node* q = 0;

while(cin >> n) 
{ p = new Node(n,q);
  q = p;}

for(;p->next; p=p->next)
    cout << p->data << "->";
    cout << p-> data << "->*\n";
return 0;}

The code above works perfectly, and can be terminated by the user using Ctrl+D followed by Enter. However if we replace while(cin >> n) with while (true) using cin >> n; inside the loop, as shown here

    while(true) 
    { cin >> n;
    p = new Node(n,q); q = p;}

then upon the user attempting to terminate, the loop just goes on automatically creating new Nodes!! Why??
Thanks in advance

Answer 1

It keeps going because the loop condition is true, making it an infinite loop. If you want to break out of the infinite loop, you can use a break statement, e.g.

while (true) {
    if (!(cin >> n)) {
        break; // exits the loop
    }
    p = new Node(n,q);
    q = p;
}