I’m still new to the business, but I’m easy to understand …
I have a Token creation solidity code, everything is going well, I can create the token with the exact amount, so far so good … but I can’t sell it.
I would like to know how to create Crowdsale or a function to sell each token for 1 ETH, that is, each 1 token = 1 ETH. I want the person to transfer ETH and receive 1 TOKEN in return.
thanks.
Maybe just like the following:
pragma solidity ^0.5.17;
contract Crowdsale {
function buyTokens() public payable {
uint256 boughtAmount = msg.value;
}
}
For more details, you can have a look at here:
Crowdsales are in OpenZeppelin Contracts 2.x (they were removed in 3.x).
The documentation is here:
can someone implement crowdsale for me in this contract?
I want to send 1 TOKEN for every 1 ETH
====================================================
pragma solidity ^0.4.24;
// ----------------------------------------------------------------------------
// Sample token contract
//
// Symbol : LCST
// Name : LCS Token
// Total supply : 100000
// Decimals : 2
// Owner Account : 0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe
//
// Enjoy.
//
// (c) by Juan Cruz Martinez 2020. MIT Licence.
// ----------------------------------------------------------------------------
// ----------------------------------------------------------------------------
// Lib: Safe Math
// ----------------------------------------------------------------------------
contract SafeMath {
function safeAdd(uint a, uint b) public pure returns (uint c) {
c = a + b;
require(c >= a);
}
function safeSub(uint a, uint b) public pure returns (uint c) {
require(b <= a);
c = a - b;
}
function safeMul(uint a, uint b) public pure returns (uint c) {
c = a * b;
require(a == 0 || c / a == b);
}
function safeDiv(uint a, uint b) public pure returns (uint c) {
require(b > 0);
c = a / b;
}
}
/**
ERC Token Standard #20 Interface
https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
*/
contract ERC20Interface {
function totalSupply() public constant returns (uint);
function balanceOf(address tokenOwner) public constant returns (uint balance);
function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
function transfer(address to, uint tokens) public returns (bool success);
function approve(address spender, uint tokens) public returns (bool success);
function transferFrom(address from, address to, uint tokens) public returns (bool success);
event Transfer(address indexed from, address indexed to, uint tokens);
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}
/**
Contract function to receive approval and execute function in one call
Borrowed from MiniMeToken
*/
contract ApproveAndCallFallBack {
function receiveApproval(address from, uint256 tokens, address token, bytes data) public;
}
/**
ERC20 Token, with the addition of symbol, name and decimals and assisted token transfers
*/
contract LCSTToken is ERC20Interface, SafeMath {
string public symbol;
string public name;
uint8 public decimals;
uint public _totalSupply;
mapping(address => uint) balances;
mapping(address => mapping(address => uint)) allowed;
// ------------------------------------------------------------------------
// Constructor
// ------------------------------------------------------------------------
constructor() public {
symbol = "ABC";
name = "Abcdario";
decimals = 18;
_totalSupply = 100000000000000000000000000;
balances[0xF320f8a4c1D123Eebc6f531978DAF7022FCeC775] = _totalSupply;
emit Transfer(address(0), 0xF320f8a4c1D123Eebc6f531978DAF7022FCeC775, _totalSupply);
}
// ------------------------------------------------------------------------
// Total supply
// ------------------------------------------------------------------------
function totalSupply() public constant returns (uint) {
return _totalSupply - balances[address(0)];
}
// ------------------------------------------------------------------------
// Get the token balance for account tokenOwner
// ------------------------------------------------------------------------
function balanceOf(address tokenOwner) public constant returns (uint balance) {
return balances[tokenOwner];
}
// ------------------------------------------------------------------------
// Transfer the balance from token owner's account to to account
// - Owner's account must have sufficient balance to transfer
// - 0 value transfers are allowed
// ------------------------------------------------------------------------
function transfer(address to, uint tokens) public returns (bool success) {
balances[msg.sender] = safeSub(balances[msg.sender], tokens);
balances[to] = safeAdd(balances[to], tokens);
emit Transfer(msg.sender, to, tokens);
return true;
}
// ------------------------------------------------------------------------
// Token owner can approve for spender to transferFrom(...) tokens
// from the token owner's account
//
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
// recommends that there are no checks for the approval double-spend attack
// as this should be implemented in user interfaces
// ------------------------------------------------------------------------
function approve(address spender, uint tokens) public returns (bool success) {
allowed[msg.sender][spender] = tokens;
emit Approval(msg.sender, spender, tokens);
return true;
}
// ------------------------------------------------------------------------
// Transfer tokens from the from account to the to account
//
// The calling account must already have sufficient tokens approve(...)-d
// for spending from the from account and
// - From account must have sufficient balance to transfer
// - Spender must have sufficient allowance to transfer
// - 0 value transfers are allowed
// ------------------------------------------------------------------------
function transferFrom(address from, address to, uint tokens) public returns (bool success) {
balances[from] = safeSub(balances[from], tokens);
allowed[from][msg.sender] = safeSub(allowed[from][msg.sender], tokens);
balances[to] = safeAdd(balances[to], tokens);
emit Transfer(from, to, tokens);
return true;
}
// ------------------------------------------------------------------------
// Returns the amount of tokens approved by the owner that can be
// transferred to the spender's account
// ------------------------------------------------------------------------
function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
return allowed[tokenOwner][spender];
}
// ------------------------------------------------------------------------
// Token owner can approve for spender to transferFrom(...) tokens
// from the token owner's account. The spender contract function
// receiveApproval(...) is then executed
// ------------------------------------------------------------------------
function approveAndCall(address spender, uint tokens, bytes data) public returns (bool success) {
allowed[msg.sender][spender] = tokens;
emit Approval(msg.sender, spender, tokens);
ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, this, data);
return true;
}
// ------------------------------------------------------------------------
// Don't accept ETH
// ------------------------------------------------------------------------
function () public payable {
revert();
}
}
Such like so.
function _mint(address account, uint256 amount) internal {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply + amount;
_balances[account] = _balances[account] + amount;
emit Transfer(address(0), account, amount);
}
function buyTokens() public payable {
require(msg.value == 1 ether, "need 1 Ether!");
_mint(msg.sender, 1e18);
}
Hi @CriptoGain,
You could look at the following example: Simple ERC20 Crowdsale.
It appears as though your token has a fixed supply.