C++ linked lists

boyracer87

Hey guys,

I have a mid term exam tomorrow(monday) and im having some problems with linked lists in C++. The lecturer gave use the following program and im having some trouble understanding it. Any help would be greatly appriceated:



[PHP]#include <iostream>
#include <string>
#include <cstdlib>
#include <ctime>
using namespace std ;

struct Node {
int Data;
struct Node * Next;
};
typedef struct Node Entry ;

void InsertFirst(int , Entry * &) ;
void DisplayList(Entry * ) ;

main()
{ Entry * Head = NULL ;
int RandomNumber ;
srand(time(0)) ;
RandomNumber = rand() % 50 ;
while(RandomNumber != 0) {
InsertFirst(RandomNumber,Head) ;
RandomNumber = rand() % 50 ;
}
DisplayList(Head) ;
}

void InsertFirst(int R, Entry * &H)
{ Entry *e ;
e = new Entry ;
e->Data = R ;
e->Next = H ;
H = e ;
}

void DisplayList(Entry * H)
{ Entry *Position = H ;
while(Position != NULL) {
cout << Position->Data << '\t' ;
Position = Position->Next ;
}
cout << endl << endl ;
} [/PHP]

boyracer87

Well the bit that is most confusing is this part and how it ties in with main:

void InsertFirst(int R, Entry * &H) 
{    Entry *e ; 
    e = new Entry ; 
    e->Data = R ; 
    e->Next = H ; 
    H = e ; 
}