Question

The question I want answered is in C++.

How can I pass a value to a function and create a new linked list out of it? For example I have:

void getIntegerInput(List<int> list)
{
   int s;
   std::cout << "Type a positive integer then click enter to add it to the linked list\n";
   std::cout << "Type -1 to stop\nType -2 to delete an item from the list\n";
   std::cin >> s;
   while (s != -1)
   {
       if (s == -2) {
           int t;
           std::cout << "This is your list" << std::endl;
           std::cout << "______________________" << std::endl;
           list.displayList();
           std::cout << "Choose from the list that you would like to delete" << std::endl;
           std::cin >> t; std::cout << std::endl;
           list.delNode(t);
           std::cout << "Type an integer then click enter to add it to the linked list\n";
           std::cout << "Type -1 to stop\nType -2 to delete an item from the list\n";
           std::cin >> s;
       }
       if (s >= 0) {
       list.addNode(s);
       std::cin >> s;
   }
   }
   list.displayList();
}

Whenever I use this function I can create a linked list, however as soon as I run another function my linked list disappears. I know I need to use pointers but I'm not sure how to implement them. How would I go about doing this?

Answer 1

#include <iostream>
#include <list>
#include <iterator>
using namespace std;

//function for printing the elements in a list
void displayList(list <int> g)
{
   list <int> :: iterator it;
   for(it = g.begin(); it != g.end(); ++it)
       cout << '\t' << *it;
   cout << '\n';
}

int main()
{

   list <int> list1;
int i;

     
  
   while(i>-1)
   {
       cout<<"ENter a positive value,Enter -1 to stop,Enter -2 to delete";
   cin>>i;
   if(i>-1)
   {
  
       list1.push_back(i);
       cout << "\nThis is Your List : ";
   displayList(list1);
}
   }
   if (i==-2)
   {
       list1.pop_front();
       displayList(list1);
      
   }
     

   return 0;

}

CAUsersldellNDocumentsVinklisttemplate.cpp [Executing) - Dev-C++ 5.11 File Edit Search View Project Execute Tools AStyleWindow Help CAUsers dell listtemplate.exe Nter a positive value Enter 1 to stop Enter2 to delete 32 his is Your List Nter a positive value Enter 1 to stop, Enter2 to delete2 his is Your List Nter a positie value. Enter 1 to stop. Enter 2 to delete3 34 35 36 37 38 39 40 41 42 43 his is Your List Nter a positive value Enter 1 to stop, Enter 2 to delete4 his is Your List Nter a positive value Enter 1 to stop, Enter2 to delete5 his is Your List Nter a positive value Enter 1 to stop, Enter2 to delete6 his is Your List Nter a positive value. Enter 1 to stop.Enter2 to delete-2 Process exited after 15.22 seconds with return value Press any key to continue. . returne 45 46 47 Resources dh compi g 22 Compiler Debug L Find Results Close - Warnings: o - Output Filename: C:Users\delll\Documents\linklisttemplate.exe - Output Size: 1.31354236602783 MiB - Compilation Time: 2.47s Abort Compilation Shorten compiler paths Line: 38 Col: 28 Sel: 0 Lines: 47 Length: 667 Done parsing in 0.016 seconds Insert 2:12 AM 5/2/2019