gistfile1.txt

pragma solidity ^0.6.4;

contract Token {
    ...
    ...

    mapping(address => uint) public balanceOf;
    event Transfer(address indexed _from, address indexed _to, uint256 _value);

    function transfer(address _to, uint _value) public returns (bool success) {

        require(_to != address(0));
        require(balanceOf[msg.sender] >= _value);

        balanceOf[msg.sender] -= _value;
        balanceOf[_to] += _value;

        emit Transfer(msg.sender, _to, _value);

        return true;
    } 

}