On Monday, 25 April 2022 at 01:40:01 UTC, Alain De Vod wrote:
Following program is a single linked list.
We expect as output 1 2 3 1 2 3
But the output is only 1 2 3
```
If you don't need List to be treated as a true range, but just
want to iterate, a simple way to do this is with opApply:
https://tour.dlang.org/tour/en/gems/opdispatch-opapply
```d
import std.stdio: write,writeln;
import std.range: empty,popFront,front;
struct Node {
int element;
Node * next;
}
class List {
Node * root=null;
this(int[] AR){foreach(i ; AR)pushfront(i);}
bool empty() const {return !root;}
/*void popFront() {root=root.next;}
float front() const {return root.element;}*/
void pushfront(int element) {
Node * newnode=new Node();
newnode.element=element;
newnode.next=root;
root=newnode;
}
int opApply(int delegate(typeof(Node.element)) dg) {
Node* current = root;
while (current) {
if (dg(current.element)) return 1; // stop iteration if the
foreach body asks to break
current = current.next;
}
return 0;
}
}//List
void main(){
List l=new List([3,2,1]);
foreach(element; l) writeln(element);
foreach(element; l) writeln(element);
}
// 1 2 3 1 2 3
```
