On Thursday, 6 April 2023 at 14:26:01 UTC, a11e99z wrote:
member func has invariant that **this** is not null (programmer
thinks so).
global func hasn't the one and programmer should check for it
before doing something ...
I understand what you mean. When you try to access the last node
of a linked list, you will get the segmentation fault if you are
using a built-in viewer (toString). For example:
```d
struct Node
{
int item;
Node * back;
string toString()
{
import std.format : format;
return format("Node::%s (back)-> %s", item,
back.item);
}
}
void main()
{
import std.stdio : writeln;
auto node1 = Node(41);
auto node1Ptr = &node1;
//printNode(node1Ptr);/* NOT COMPILE!
node1.writeln;//* Main::41 (back)-> null */
auto node2 = Node(42);
node2.back = node1Ptr;
printNode(&node2); // Main::42 (back)-> 41
node2.writeln; // Node::42 (back)-> 41
}
void printNode(Node * p)
{
import std.stdio : writefln;
if(p.back is null)
{
writefln("Main::%s (back)-> null", p.item);
} else {
writefln("Main::%s (back)-> %s", p.item,
p.back.item);
}
}
```
If you don't remove the comment line (just remove the // sign:
toggle-comment) the above code will not compile. Because it is
not connect to any node.
@SDB
