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Basic ERC20 implementation
pragma solidity ^0.4.19;
contract ERC20Basic {
string public constant name = "ERC20Basic";
string public constant symbol = "BSC";
uint8 public constant decimals = 18;
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
event Transfer(address indexed from, address indexed to, uint tokens);
mapping(address => uint256) balances;
mapping(address => mapping (address => uint256)) allowed;
uint256 totalSupply_;
using SafeMath for uint256;
constructor(uint256 total) public {
totalSupply_ = total;
balances[msg.sender] = totalSupply_;
function totalSupply() public view returns (uint256) {
return totalSupply_;
function balanceOf(address tokenOwner) public view returns (uint) {
return balances[tokenOwner];
function transfer(address receiver, uint numTokens) public returns (bool) {
require(numTokens <= balances[msg.sender]);
balances[msg.sender] = balances[msg.sender].sub(numTokens);
balances[receiver] = balances[receiver].add(numTokens);
emit Transfer(msg.sender, receiver, numTokens);
return true;
function approve(address delegate, uint numTokens) public returns (bool) {
allowed[msg.sender][delegate] = numTokens;
Approval(msg.sender, delegate, numTokens);
return true;
function allowance(address owner, address delegate) public view returns (uint) {
return allowed[owner][delegate];
function transferFrom(address owner, address buyer, uint numTokens) public returns (bool) {
require(numTokens <= balances[owner]);
require(numTokens <= allowed[owner][msg.sender]);
balances[owner] = balances[owner].sub(numTokens);
allowed[owner][msg.sender] = allowed[owner][msg.sender].sub(numTokens);
balances[buyer] = balances[buyer].add(numTokens);
Transfer(owner, buyer, numTokens);
return true;
library SafeMath {
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
assert(c >= a);
return c;
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tobbhie commented Mar 20, 2022

add emit

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