Created
December 5, 2018 00:03
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ZeppelinOS - LinkedList Tutorial code
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pragma solidity ^0.4.24; | |
import "zos-lib/contracts/Initializable.sol"; | |
contract LinkedList is Initializable { | |
event AddEntry(bytes32 head, string data, bytes32 next); | |
//Struct will be our Node | |
struct Node { | |
bytes32 next; | |
string data; | |
} | |
//Mappping will hold nodes | |
mapping (bytes32 => Node) public nodes; | |
//Length of LinkedList (initialize with constructor/initalizer) | |
uint public length; | |
//Head of list; | |
bytes32 public head; | |
function initialize() initializer public { | |
length = 0; | |
} | |
function addNode(string _data) public returns (bool){ | |
Node memory node = Node(head, _data); | |
bytes32 id = keccak256(node.data, length, now); | |
nodes[id] = node; | |
head = id; | |
length = length+1; | |
emit AddEntry(head, node.data, node.next); | |
} | |
//popNode | |
function popHead() public returns (bool) { | |
//hold this to delete it | |
bytes32 newHead = nodes[head].next; | |
//delete it | |
delete nodes[head]; | |
head = newHead; | |
length = length-1; | |
} | |
//Contract interface | |
function getNode(bytes32 _node) external returns (bytes32, string){ | |
return (nodes[_node].next, nodes[_node].data); | |
} | |
} |
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